Once you have successfully been accepted to drive a relocation car or campervan, you will receive a booking confirmation email that will contain all the information about the pick-up address and pick-up time of your vehicle at a rental operator's branch.
Go to the branch on time, show your driver's license and valid credit card, and the staff at the counter will happily hand over the car keys to you!
Note: As in a normal rental, you will still have to go through an inspection of the conditions of the vehicle with the staff before and after the trip. You're expected to return the vehicle in a good condition!