Is there a way to add/limit capacity of attendees for a session?

Yes! In order to change the number of attendees allowed in a session, you'll need to use the Session Cap add-on tool.

To enable the Session Cap, please access:

1. Attendees > Session Cap > click Enable

2. Click Add Sessions

3. Search for the Session and check the little box next to it > Change the limit number of attendees in the Set Capacity section > Click the Save button.