While your account uses Gmail, you won't be able to sign in at the normal Gmail sign in page at mail.google.com. Instead, you'll be signing in at mail.upou.edu.ph.
The form will look similar to Gmail and have most of the features of Gmail.
Your username is in this format:
The domain "@upou.edu.ph" will automatically be appended. Your password will be what was assigned to you or some other password you set. If you cannot remember your password, sign in to your UPOU Network Account and reset it.