If you wish to link your MyMSTeam account with your Facebook account, when you go to sign in on the homepage, click the Sign up with Facebook prompt. You will need to allow MyMSTeam to connect with your Facebook account. After that is done, you will be directed to log in with your email address and password for Facebook.
You can share your MyMSTeam updates on Facebook if you click the box that allows that:
If you have any questions about this feature, feel free to contact Support here.