Single Round robin you play everyone once. Double round robin you play everyone twice (once with each color). Decades ago most professional tournaments were double RR because it was considered the truest test of who was best in that tournament - and fairest because you got both colors against everyone. Most major tournaments now are single RR.
Swiss system is to whittle down a very large group in a few rounds (like in most weekend touraments). Say you have 64 people, in every round you have 32 games. If every game is decisive you'll have 32 winners. In round two you pair the 32 winners against each other (and the 32 losers against each other). So, at the end of two rounds you'll have 16 players that are 2-0. Then you pair them and after 3 rounds you'll have 8 player 3-0. etc.
What are the different types?
I know about Round-Robin, but have no idea what that is.
I also know about swiss pairings and carosel, but are clueless as to what those are.
What are they? What other tournament types are there?