How to set automatic timer for Teams breakout rooms ?

Niewe features for Microsoft Teams Breakout Rooms are rolling out now! (April 2021)

Timer: Organizers can now set a timer for brainstorming rooms from within the brainstorming rooms. After the timer expires, rooms are automatically closed and participants return to the main meeting.

Retain configuration and allocations: Retain breakout rooms provides the ability to retain room configuration and allocation across multiple sessions.

Move people through rooms and main meeting in brainstorming rooms: with the ability to reassign participants, the organizer can now move merged participants through rooms and main meetings even when rooms are open.

Set a time limit?

Press settings -> room settings -> then select the desired time you want to set for the breakout room.

All about breakout rooms!

Read -> Tutorial: Microsoft Teams breakout rooms !