In the Module content under "Hotels/Rooms" you have several options, "Max. number of rooms" and "Max total number of rooms".
In case you want to set a limit on the number of rooms a participant can choose on the "Hotel bookings spec." (see below), choose for option 1.
In case you want to set a limit on the number of bookings a participant can make, choose for option 2.
Explanation of the other setting in the screen:
'Hide Rooms When Maximum Is Reached' and 'Text Shown When Maximum Is Reached' are explained on this page: Use the event counter and hotel counter
'Text Shown When Maximum Is Reached', if you don't hide the room when it is full, you can choose to add a text behind the room stated that is is full.
'Restrict Hotel Dates', Restricts the arrival and departure dates of hotel bookings to the start and end dates of the hotel contract.
'Skip Hotels Page After Room Selection', when you check the box, the participant will go to the next screen instead of back to the hotel page.