After signing into the Columbus Academy SchoolPass site as described in the email to register your new SchoolPass account, you can install the app on your smartphone / tablet. Remember that if you have a Google @gmail or Google-hosted email account you should use the "Log in with Google" SSO (Single-Sign-On) option, and similarly with Apple SSO for @icloud or @me accounts.
Each parent can make add, remove or modify your car tag/plates on their own SchoolPass profiles, while most household contact details are locked in SchoolPass, as they are linked to accounts in mySchoolApp (Blackbaud).