iCal doesn't require any access rights. Only the information provided in the iCal (It depends on how it is generated.) will be shown.
It doesn't allow Auto-Release with ROOMZ Sensors.
Go to Setup - Booking System, and register a new iCal connector
Select Add resource and define the friendly name of the resource. In Resource ID, paste the *.ics link you generated from your email account, or your booking system and click Save and add
Test the connectivity with Test all
The resource can now be linked to a workspace, as explained here.