Once you’ve joined the meeting, your meeting controls bar will appear at the bottom of the Teams screen.
To change your devices or record a meeting, click on the ellipsis. (See this article for more info on Teams recordings)
To share your screen or a document, click on the share icon and select the desktop or document you wish to present
When presenting, move your mouse to the top of the screen or document being presented to reveal the presentation control bar. When done presenting, click “Stop presenting” to return to the full Teams screen.
If you wish to return to the full Teams screen while presenting, click on the small floating Teams screen. You also have access to a mini controls bar here.