If the reservation is room-only, then you pay a one-night deposit, with the remaining balance due when you check-in. They charge you then for the room. For charging other purchases during the rest of your trip, they can swipe your credit card for verification, but they will not place a hold or charge anything. You will be given a charge limit, which varies by resort type (I think it's $500 for Values, $800 for moderates and $1000 for Deluxes). If you go over that limit you can tell them to make a charge to the card or pay in cash, and your limit will be restored. At check-out, you'll get a statement on your door. You can choose to charge it to the card on file, or use another method of payment.
You can also choose to leave a cash deposit, and your charges will be deducted from it as you go along.