what does Time Control: 5 rounds, G/30;d0 mean?

Tournament is 5 games with a 30 minute time control for each side for the whole game (not for a set number of moves). There is no delay setting. (Some tournaments use a setting where the clock start is delayed by a number of seconds after every move.)

5 games? does that mean you play each person 5 times? that would take forever. there's no way they could know how many games will be played because that would depend on how many people show up

No, I never played the same opponent twice in a tournament (and I played dozens). You play 5 different opponents.

Most amateur tournaments use a system where the first round is paired by rating (with highest rated against middle rated and so on moving down the list) and subsequent rounds are paired by cumulative score. So, for the 3rd round, those with two wins would play; those with 1.5 play each other; and so on, as much as possible. That is called the Swiss System.

The other possibility is a round robin, where each player plays each of the other players. Round robins are usually used in grandmaster tournaments and sometimes in very small events.

The tournament listing normally tells how it is organized. Please post the full listing.

I think I understand now but here it is anyway. but what if they are so many people that 2 people win all 5 games (because they never played each other) they can be more than 1 winner? Time Control: 5 rounds, G/30;d0 Start Times: Approx.~(12:00) - 1:45 - 3:15 - 4:45 - 6:15 Entry Fee: $30 New to USCF players can play for FREE Prizes: Class Prizes based on the following: Expert+ (includes Masters), A, B, C, D, E, below 1000 Sections: Open, Quads, Multi-sections, it all depends on the rating spread of all the players. We try to be as fair as possible and will accommodate requests of playing 'up' and trying to avoid pairing friends and family if possible. Membership: USCF membership required. All games are USCF rated.

this is the worst web app in the world, formatting sucks and there no way to edit or delete a post...

You'll have to check to see what the tie-breaker rules are.  When I was USCF Tournament Director for my county's scholastic chess, I ran 5-round Swiss system tournaments and if I had people tied for any trophy (overall 1-2-3, under 1200, 1000, 800, unrated, trophy, etc.), I ran unrated, 5-minute-clock blitz playoffs to break the ties, with a coin toss deciding who got White.

Daryl - for some reason they hide the edit/delete choices.  Hold your cursor over the quote marks (") at the top right of your post and edit and delete symbols will appear to the left.