The stickman will deduct the losing three bets from your payout and leave the whole bet up. Crap bets are one roll bets. In other words, you are betting either that the number four will come up as two twos, or that six will come up as two threes, or eight as two fours, or ten as two fives. These bets are not one roll bets. Hardways also lose on seven.
Craps is a confusing, loud, raucous game for a beginner.
Don't be intimidated by the complex layout. Try to find a quiet game and a helpful dealer. Many casinos have classes, usually in the late morning. Always take at least some odds on the pass line or the don't pass. Always bet increments.