Teams - Syncing your Teams team files to your File Explorer
Open the Teams team of which you would like to sync the Files-tab to your File Explorer
Click the Files tab and click the Sync button.
Your OneDrive will open up, follow the prompts (log in if you weren't already).
From now on your File Explorer will show a seperate button to indicate your Teams files are now being synced.
! IMPORTANT SIDENOTE !
This sync uses the OneDrive client installed on your computer.
If your OneDrive is not opened up or is not syncing, you will not see the latest version of all of your files.