In order to add reservation for multiple rooms, you can use booking option in eZee Frontdesk. Please refer below screenshot for more detail:

Once you complete step by step booking process, it generates booking number. You can assign rooms to this booking transaction when required.Please refer below screenshots for more details:

You can select total number of room types as per availability in hotel.

You can assign rooms to selected room types using "Group Rooming" option as shown below: