Connect the messaging app Microsoft Teams to your SharePoint Online O365 group-connected team site by creating a Team. Communicate through chat, meetings, and calls.
Note: If you don't want to create a Microsoft Team for your SharePoint site, simply click the x at the top of the Microsoft Teams banner in the bottom left corner of your site and then click Yes to dismiss the banner for the current browser session or click Don't show me again to remove the banner permanently from your site.
To create a Microsoft Team from SharePoint:
Go to a group-connected team site you own
Select Create a team in the lower left hand corner of the home page
A link to the team will be added to the site navigation.
If your Office 365 Group has a team already, add it to the site navigation, instead
Connect the Office 365 Group to your existing team site
Note: This functionality will be introduced gradually, first to organizations with targeted release options selected in the Office 365 Admin Center. You may not see this feature, or it may look different than described here.