Step 1: Launch or Join a Teams Meeting
To launch or join a meeting in Teams, click on the Meetings tab (on the desktop app, this is on the left side of the app). If your organization uses the Outlook calendar, Teams will pull that data into the Meetings tab. You should see a list of meetings here.
If you’re joining someone else’s meeting, you should see it in the list. Simply click “Join”. If you’re launching your own, click “Schedule a meeting” at the bottom of the column. Fill in the relevant details and pick a time. (It can be right now, if you need.)
Bonus tip: If you’re the one scheduling the meeting, make sure to invite the relevant teams or people. Use the Scheduling Assistant to see when your participants are free.
Step 2: Find and Click the Share Button
Once you’ve joined a Teams meeting (either as host or participant), you’ll see a set of buttons whenever you move the mouse. The video camera and microphone are fairly self-explanatory, but the button that comes next is a little less obvious. It looks like a rectangle with an up arrow in it. This is the Share button. Click it to bring up the Share menu.
You can share all sorts of things, but PowerPoints are what we’re after here. You’ll see a section with some suggested PowerPoints. Microsoft attempts to guess which OneDrive or SharePoint files you might want, but if it fails to suggest the right ones, you can always navigate yourself by clicking “Browse”. Click on the file you want, and it will launch into the Teams meeting.
Source: Microsoft