Microsoft Teams is a collaboration app that helps your team stay organized and have conversations—all in one place. Here's a quick look at the left hand side of Teams.
Teams – Find channels to belong to or create your own. Inside channels you can hold on-the-spot meetings, have conversations, and share files.
Meetings – See everything you’ve got lined up for the day or week. Or, schedule a meeting. This calendar syncs with your Outlook calendar.
Calls – In some cases, if your organization has it set up, you can call anyone from Teams, even if they’re not using Teams.
Activity – Catch up on all your unread messages, @mentions, replies, and more