This way, their seat will be included in the maximum number of attendees for the service.
You can't add participants to the group service itself. You have to add them to a specific occurrence in your calendar.
Step-by-step guide:
Go to your Admin page.
Open your Calendar
Click on the occurrence of the group service where you want to add participants.
Click on the “Add participant” button.
Enter the contact details of the participant or select from your existing clients.
Name
E-mail
Phone (Optional)
Booked seats
If your guest would like to attend at this same time regularly, check the “Regular participant” box.
Click on the “Save” button in the participant editor.
Click on the “Save” button at the bottom of the occurrence editor. The participant will receive an automatied confirmation email.