1) Go to Settings -> Site Security then click Add.
...
6) To restrict access to information to a user that is a member of a team, configure "Users can only see Teams they have permissions on" to "Yes" in the top menu:
1) Go to Settings -> Site Security then click Add.
...
6) To restrict access to information to a user that is a member of a team, configure "Users can only see Teams they have permissions on" to "Yes" in the top menu: