Open the Play Store on your phone's home screen
From the landing screen of the Play Store, click Search
In the Search Bar along the top type Duo Mobile and click on the 1st entry it finds
You will then see this screen - Ignore the Sponsored app and click on install for Duo Mobile.
IT will walk you through how to set up Duo after you get it installed.
Once Duo is installed, go back to the Search in the Play Store and Search for Outlook for Android
You will then see this screen - Ignore the Sponsored app (this time it's actually for the correct app) and click on install for Microsoft Outlook.
Again, IT will walk you through how to configure the app.
Finally, go back to the Search one more time and search for Teams for Android
You will then see this screen - click on Install for Microsoft Teams.
IT will again walk you through what you need to get the app configured.