Since Microsoft Teams were released after (and are built on) Office 365 Groups, Microsoft has provided a quick solution for adding Teams functionality to an existing Group. (NOTE: A Group must have less than 999 members for the conversion to be successful.) This solution can be completed in just a few simple clicks.
The process is very similar in both the Teams desktop app and the web interface within Office 365. To start, begin creating a new Team.
Notice that the wizard detects that you are an admin of an existing Group. Simply click the option “Yes, add Microsoft Teams functionality”, then select the Group.
Voila, your Group is now a Team!
Something to be aware of is that the the files you had previously uploaded to your Group may appear to be “missing” within the Teams interface. In the document library, you will find that there is a folder for each channel created within the Team. The default Files tab with point to the “General” folder.
If you would like to see your other documents, you can either move them into a channel folder upon initial creation, or add a tab to the document library.