If your studio has set up a member management system with an interface to EGYM, create the member profile only in the member management system.
Alternatively, you can always create a new member directly in the EGYM trainer app. Click on the tab called members and then on the top right of the screen on the + sign. Here you can create new members by adding the email address and first- and surnames.
Please note: a personal email address is mandatory for an EGYM account, i.e., not a shared email address to ensure storing training results with the correct person.