how exactly do bids work?

One bid on bid day, unless 1) you unsuccessfully suicide (only list one house when you had up to 3 you preffed at) or 2) dont maximize your options, for example, you only list two on your bid card even though you preffed at 3 houses...in either of those 2 scenarios you might end up released from rush with no bid,

Let say you go to 3 prefs. You rank all 3 houses in the order you liked them 1) A, 2) B, 3) C. If you are high enough on A's bid list, you will get A. If not, if you are high enough on B's bid list you get B. If not, if you are high enough on C's bid list you get C. If you are not high enough on anyone's bid list, but you maximized your options, i.e. listed all the house you preffed at...you typically still get a bid, very possibly at your top choice, as a quota addition. It is kind of like a thank you from Panhellenic for keeping your mind open and playing by the rules.

If you suicide and are not high enough on the bid list for the house you wanted, then rush is over for you, you don't qualify to be a quota addition and you will not get a bid.