How to sync SharePoint sites to your computer
1) Go to your email and open the invitation email you have received from the SharePoint site.
2) Inside the invitation email, click on view group.
3) Go to the groups section in your Outlook and click on the team site name.
4) At the top of the Outlook, in the home taskbar, click files.
5) Inside the team site page, click on documents and then click on sync to start syncing the team site to your computer.