The registration category grid area down the bottom of the event registration setup screen is used to define who is eligible to attend the event, and the parameters governing each registration type - including whether the registration is for In-Person or Remote/Virtual attendance.
The system uses these categories to display the appropriate registration information to registrants and to restrict registration to persons entitled to attend.
Each line in the grid defines the categories to be made available for registration. This is also where registration categories are designated as in-person attendance or virtual/remote attendance via some flag settings in Reference Data Management where the Event Registration Categories are defined:
In reference data, each applicable registration type should have a corresponding "Flag" checked on to indicate to the Gnosis system whether the registration category is in-person or virtual. This in turn triggers the appropriate iconography and options to appear on the calendar and elsewhere.
The full reference on setting up for virtual/hybrid events is available here: Initial Setup Hybrid Event Management