To log into your @nbseminary.ca email account account go to http://mail.nbseminary.ca. That link will open the Google Account sign-in page. Sign in with your @nbseminary.ca email address and your password.
If you have another Gmail account you might need to log out of that one and log back in to the @nbseminary.ca one. You can view which account you are logged into like this:
You can then log out and back in like this: