Full answer
You do not need to be family to have your hair and makeup done with the bride's team on the wedding day. Any guest can book it, which helps when you have travelled to Spain and do not know a single salon nearby.
Where a guest gets her hair and makeup done
If you are close to the bride, you can get ready in her room with the rest of the group. If not, part of the team comes to your hotel room and gets you ready there, without you having to go anywhere.
How a guest fits into the wedding morning
Your booking becomes part of the whole morning's schedule, which is worked out backwards from the ceremony. There is no special slot for you: the team gets you ready whenever the schedule allows, between everyone else getting ready.
How a guest's service is paid
A guest's service is paid in full on the wedding day, with no deposit or earlier payment.