It will work the same way as a cash rental from Disney. You go to the check-in counter, present your Driver's license of photo ID. They check you in, and if you have the
DDP, you pay for it at that time. You may leave a credit card on file for purchases throughout WDW, using your room key as a charge card. Your room may not be ready for occupancy, as
DVC resorts are designed to operate at a higher occupancy level overall than the cash resorts. But, it may be ready early...just luck of the draw.
If it isn't ready, you can leave a cell phone number, and an automated system will contact you when it is ready, or you can check-back later.
The basic difference between DVC and a cash rental is when a DDP payment is made, and less housekeeping days.