The Tile View Button
You may want to divide your display between the video feeds from all participants equally; view your video feed larger than all other participants; or change the size of the video feed on your screen according to who is speaking.
The tile view button can help you make changes to how you view your screen during a video call.
It displays four square windows. You can find it next to the 'Raise/Lower Your Hand' button, to its right.