The PASSLINE really is the lifeline of the game of craps. When you stand at the craps table, you are actually playing many, many, many games of craps.
The PASSLINE is easier to understand once you understand, it's what starts and ends the game.
The idea of the passline, is to roll a POINT NUMBER on the COME OUT that is 4,5,6,8,9,10. If one of these numbers is rolled, then the games is ON. Now you can either win, or loose, based on the POINT NUMBER. If you roll the POINT NUMBER again before you roll a 7, you win. If you roll a 7 before the POINT NUMBER, you loose.
Is that's simple.
So now, what happens if on the COME OUT, you roll a number that isn't a POINT NUMBER? These would include 2,3,7,11,12, and you'll either loose your passline bet, or the house will pay you. You've heard them yell 7 or 11. That's because these number PAY on the COME OUT. If you have $100 on the PASSLINE and 7/11 roll, you WIN another $100. 2,3,12 are named CRAP DICE. On the COME OUT, crap dice are loosers, and you're out a c-note.
Now you know everything about the PASSLINE, except the odds bet that sometimes you see people put behind or BACKUP their original bet.
Do a search for TRUE ODDS to find out how these bets work, and why everyone, even the casinos, will tell you, this is the best bet in the casino. Basically if you play the PASSLINE and don't BACKUP your bet with true odds, you're wearing a sign that says "I'M AN IDIOT"