The first time you run Apple Mail, this dialog will automatically open. If this is not the first time you have run Apple Mail, you can get to the dialog by going to Preferences > Accounts. Click the + button to add an account. Select Google. Click Continue.
Continue by logging in with your full SAS email address,
and your Google@SAS password and click Next.
You can then select the apps you want to use with this account and click Done.