Openings were first for me, but I didn't understand them. I memorized a lot of them, but no one played the opening right--they always deviated in the move order. So I wasn't really learning the openings, afterall.
In which order did you learn chess?
If I was to do it all over again I would have wanted to learn with several pieces at a time. Starting with pawns, then pawns and king, then add bishops, then take the bishops off and add rooks, then take rooks off and add a queen, then take the queen off and add knights, ect. I was taught the hard way though with all the pieces on the board and slowly learned how each moved. Obviously I managed to understand it (I was 7 at the time) but I bet it was harder than it needed to be.
But you seem to be talking about beginners starting to play chess (already knowing how the pieces move and rules). I strongly advocate beginners to play only "end game" positions with a few pieces. Mastering the basic king and pawn/s, king and minor piece and pawn/s, king and major piece and pawn/s end games seem to help players understand how pieces work together without being confused as easily. It also teaches them how to be accurate, to calculate, along with some basic principles to help guide their move choices. Reinforces rules of how perpetual checks, stale mates, insuffient material to mate, and even sometimes three fold repetition works too. I wish I had learned this way as a child honestly because going back to do this now is harder and having to correct bad habits is harder than just learning good ones from the get go. Learning simple, few piece tactics along with this helps too, and eventually going on to normal position tactics as they grow in understanding (and strength). Same with eventually playing regular games, once they seem to understand end games pretty well and how a few pieces interact with each other.

First topic? Openings I guess which I used to try and blindly memorize reams and reams of when I was in High School - and I never even got high back then which would have been a much better use of all the time I wasted on memorizing opening theory, 90% of which (at least) I quickly forgot and was probably outdated or refuted not long afterwards anyway.
Here's some good advice on improving from Capablanca:
In order to improve your game, you must study the endgame before everything else. For whereas the endings can be studied and mastered by themselves, the opening and middle game must be studied in relation to the end game.
The best way to learn endings, as well as openings, is from the games of the masters.
The game might be divided into three parts, the opening, the middle-game and the end-game. There is one thing you must strive for, to be equally efficient in the three parts.
You may learn much more from a game you lose than from a game you win. You will have to lose hundreds of games before becoming a good player

I learned how to move the pieces and then I started playing a few games with family members learned from my mistakes and kept playing the game.

I learned piece movement in a classroom setting, but then spent the first months into the summer doing only tactics puzzles from the CT-Art program. I also played one or two games with a friend in that time.

I started with the basic mating schemes (K+Q vs. K, K+2R vs. K, K+R vs. K),
then the most important simple endgames with one pawn (K+P vs. K, K+P vs. K+Q etc.),
then some tactics (main motives like pin, double check, discovered check, fork, deflection - simple one-movers at first, subsequently making the lines longer),
puzzle like mate-in-2 or simpler combinations,
then the openings - at first trying to understand key ideas and memorize main lines, then more understanding
meanwhile (since the tactics stage) studying annotated master's games - hiding the score, trying to guess the next move and comparing with the actual text and what annotations explained; I tried to figure out longer lines by moving the pieces on the board and worked hard to find out why I guessed wrong in case there was no annotation for the move (it was the 90's and no engines of usable strength were available, all I could do when in doubt was to ask the more experienced players in my club - those times were good for improving social skills of chess players )
then strategical motives (fight for the centre, development, pawn structure, piece configurations - bishop pair, B vs. N, Q+N, R+B etc.)
then everything again but on a higher level (more complex endgames, longer tactics, more advanced puzzle, openings and positional ideas
I played lots of games to check the results of my work. Mainly 15|0 and 5|0 but also quite a lot of 30|0 and longer games. After a 15|0 tournament I tried to record the games I had played and analyse them. On the classics it was easier as I recorded live.
I never had any coach, only got advices from more experienced players from time to time and mainly working with the books. I cannot say it is an excellent method - my highest FIDE rating was merely 2138 which is not anything great. I am just an experienced patzer

I stuied a book called "Teach yourself Chess" when i was a boy (many moons ago)
The endgame came first I think. Followed by tactics/positional play/pawn structure.
Openenings appeared about three quarter way into the book. To a non-chess player this may make no sense, but it really does.

I think its interesting to see that just about everybody does it differently. I especially appreciated the comments from the folks that learned the opening first. If we had a few more comments, maybe we'd start to see a theme.

Opening Tactics then Endgames.
That was the order of interest I had for them. Now I enjoy endgames and spend most of my study time on them.

My dad had a few old books, those were my first books when I got interested. I don't think he ever read them. He taught me how the pieces moved and the basic mates though. One of the books was Bobby Fischer Teachs Chess (a mate puzzle book) and the other I read was on basic endgames.
Later I got an old copy of the chessmater program and found out different openings had names and such. Openings have always been boring to me, so I never was one who sat and memorized a bunch. But it's true whenever I lost badly and early in the game I'd use the chessmaster program to see what the book moves were. Like Trysts said no one played the "right" moves though so I didn't find it very useful. I wasn't playing in tournaments though, just online speed games. Oh, and I got Reinfeld's 1001 sacrifices and combinations book (a tactical puzzle book) and worked through them. This was before the internet had puzzles for you :p
Years later I wanted to improve and studied the endgame and middlegame strategy. I've yet to take openings seriously... which is my next goal in chess actually, to finally make an opening repertoire! :)

My brother taught me chess (rules only) when I was 4, and we used to go through Bobby Fischer Teaches Chess togther as well. He was 8, and obviously won almost every game we played for a long time. In middle school, I joined a chess club, and learned about pins, forks, etc. I played a couple tournaments, ended up with a 708 USCF rating after 10 games, and dropped chess again for a bit. I got back to it in college, and from sheer experience from playing here and there, could calculate better than the average player, and knew more what to do. I still didn't know what a passed pawn was (though I did know en passant), and if you asked me to show you the Sicilian, I wouldn't have been able to. I could however visualize the board up to about 6 moves ahead (12-half-moves), so exchanges and simple tactics were how I won games.
19 years after I learned the rules, a class-A player came into our lounge, and absoultely annihliated me, and the other best player that regularly hung out there, at the same time. Then I started getting serious. I began doing tactics and playing online games. I learned a few opening setups. I bought a Diamond membership to chess.com and immersed myself in videos.
I played that class-A player a bit, and he was able to assess my strength (around 1200 he said "So, a decent amateur?" I replied. "No, a decent amateur is 1600."), and was able to beat me when I made a mistake, for the right reasons. That really helped, because when I made a grevious error, I regretted it all game. I didn't lose 35 moves later from some mysterious checkmate--I was kicking myself all game for the weakness I created that he was exploiting. It helped me see what an error was, and -why- it was an error. He really got me on the right track.
I got some chess books to work on openings, found them lacking, and went to Silman's "The Amateur's Mind" and went through that with my brother over a summer. I've since went on to play more tournaments, and learned to love endgames. I have about 4 middlegame books, 1 endgame book (Silman's Complete Endgame Course), and about 5 opening books, of which I only actually use two.
I'm now over 1600 USCF, love endgames, and play Online chess here mostly, until I can get back to OTB tournaments. Finally a "decent amateur".
tldr; Learned rules early, learned basic tactics, got calculation from raw experience, dived into everything chess, succeeded studying tactics and middlegame positional chess first, then endgames, all the while playing full correspondence games.

My father had bought me a chess book when I was ~7
I remember on one of the first pages was written in bold : "After your opponent plays a move, try to figure out if this move contains a threat".
Invaluable !

i beleive the way i started learning chess was the proably the most correct way of begining with just some simple small little book that taught the very basics of chess but yet some of the most important things it taught basically everything there is about tactics tips on how to play the opening and the andgame without even going past the third move because of that book i beleive i could play at 1200 rating level at that time and the main ways i learned from their was from youtube videos of jrobi of course he wasn't a very good player but he was a very good teacher for low rated players then i started watching chess network on youtube and started playing blitz here i had never touched a long time control game until a year ago

Pretty sure we've established that there is no one correct way to learn chess. So if you're searching for ultimate truth, it's probably the wrong location to look. However if you're searching for truth in a pawn ending, you might find it more clearly ;).

I learn cheapo openings first. Anyone remember Pandofini's Chess Openings: Traps and Zaps? Good for winning againts patzers but useless against average players.

Learned the rules of chess around 7 or 8 from my father
Did not play seriously until I was in highschool.I was forced to choose a sport for my PE class and chose chess because I hate "sports".I got hooked.
I only read one book about general principles around this time.
Played internet chess in college.I fancied myself as a tactician.Always setting up tricks in every move.
Last year I learned the openings and had a tremendous surge in improvement.That is why I dont believe the adage that you have to learn the endings first before anything else.
"I say learn the things you enjoy first because if you force yourself to learn something that is boring to you,you will lose interest anyway and probably quit the game altogether"
I am now studying endgames
I stared at a checkered tile floor and thought about chess when I did not want to listen to the person talking to me. It was actually opening theory that gave me the first inkling that the game could be studied systematically. My first two chess books were Silman's Reassess Your Chess Workbook, and complete chess strategy. I have not been systematic with my studies, I look at whatever interests me at a particular moment.
I hear that the endgame is the best place to start learning chess. I've also heard that tactics are best, or simply playing a lot of slow games and analyzing them is the best way to start learning.
What was your first topic when you started learning chess?
(add anything else you think is relevant)