Office 365 Group Calendar in Teams
You are able to add your Teams Calendar (from Office 365 Groups) into a Apps Tab.
This enables you to seeing your related appointment faster.
Disadvantage is, you can navigate through Outlook Web App as usual. This is generally not an issue an further more, it allows you also writing emails from within TEAMS!
Not, you only see in OWA the content from the user you logged in with.
Ok, lets start:
Got to Outlook Web App
Hope you find this helpful and experiment with more possible Tabs/ Apps in Teams.