You can add your frequent flyer number, hotel membership card, and other loyalty programs to your profile. 

Add this info in your settings by clicking Profile, then Memberships. On this page, you can save your different memberships.

During the booking process, you can also add hotel memberships. If you’ve saved any, the system will show you the ones that can be used for the reservation. If you don’t see your membership, you can also add it during the booking process by clicking Add membership.