Due to the coronavirus crisis we've had to move to an appointment only basis, probably for the foreseeable future. You can make appointments via Apple's Support pages:
Please note that currently appointments are filling fast. This isn't unexpected - if you can't see any available appointments please check later or give us a call. Appointments open on a hour by hour basis, and are only available a week in advance, so for example a 10am Wednesday appointment for next week would open up at 10am this week.
Thank you for your patience and understanding.