To edit these bookings add the calendars to your google calendar by clicking the "+ Google Calendar" buttons below.

To book a resource go to your calendar. 

(you will need to be logged in with your username)

Click the time you want to book and in the 'Event' popup

Select 'Edit Event'

On the right hand side click on 'Rooms etc' (even if booking a vehicle)

Select the resource you want to book.