Hub Appointment Book
Pre-Requisites

In the GP Practice make sure the Appointments Data Sharing Agreement under Appointments > Viewing other organisation's appointments has been Activated:

EMIS Hub

In the Hub make sure the Appointments Data Sharing Agreement under Appointments > Sharing my appointments has been Activated:

Navigate to Appointment Book > Appointments Configuration go to Organisation Options > General and check the Allow unregistered patients to be booked by an external organisation:

When creating Appointment Books in the hub, in the Slot Properties ensure Externally Bookable is set to Yes- Allow unregistered patients: