When you are making your purchase choose your arrival date. After paying online you will receive an email with your receipt of purchase and reservation code.
On your day of arrival, enter the car park normally, take your ticket at the entrance and park in any free parking space.
When you wish to leave the car park again you need to use the intercom and provide the help centre with your reservation code before they open the barrier for you.
Carrer del Bon Orde 7