When a member's record is created in the Administration System, each record is given a unique identifier, known as an Address Code.  This address code consists of the first 4 characters of the surname followed by the customer's initial followed by a 2-digit number.

To use the Address Code in a booking, from the individual booking screen, shown below ...

Enter the Address Code into the 'Name' field of the grid.

When you press Enter to move away from the field, the member's name and address code will be filled in.