Start 1:1 or group chats to collaborate with a smaller group or to talk privately, and pin chats for quick access.
Start a chat
In Chats, you can have 1:1 or group chats with people.
1. Select New chat 
2. Type the name of the person or people you want to contact.
3. Select the down arrow to add a name to your chat group.
Make video and audio calls from a chat
Select Video call 
or Audio call 
to call someone directly from a chat.
Pin a chat
1. To pin a chat, select More Options > Pin. The chat appears in the Pinned list.
Note: You can pin up to 15 chats.
2. To unpin a chat, select More options > Unpin
See link for video: https://www.microsoft.com/en-us/videoplayer/embed/RWedV6?pid=ocpVideo0-innerdiv-oneplayer&postJsllMsg=true&maskLevel=20&market=en-us