In 'Schedule' or 'Calendar' tab, select the session of your choice.
Step 1: Click on 'Manage bookings'.
Step 2: Search for the member in the search bar.
Click on 'Book In'.
Step 3: Select a valid pass that the member possesses or invoice a new one using the 'Bill a new pass' tab.
If you want to book the client on multiple sessions, you can do so by clicking on the black calendar :
If a member has a pass and it is not appearing as compatible, follow the steps in this article: Manage the compatibility of your passes with your activities/workshops