In the README.md file JamfSchool is listed as a supported MDM. Allthough in JamfSchool it is possible to configure automated device enrollment profiles there is no way to install a package during the enrollment process. I checked with JamfSchool support and they confirmed that at the moment they (unfortunately) don't offer the installation of packages during ADE. I suggest the removal of JamfSchool from the list until they implement this feature.