Install teams Desktop. Official Link given below,
https://products.office.com/en-in/microsoft-teams/download-app
If Dev mode is enabled, Right-click the Teams tray icon and choose Open Dev Tools.
Else, Enable Dev Mode by following below steps,
Open Show hidden items to see the Teams tray icon
Click Teams tray icon 7 times. (Normal left click)
Now right click the Teams icon and you'll see all Dev options.
Update:
Now a new menu called DevTools opens as shown in image. Previously lot of dev options will show directly.
