Make sure you've selected the correct type here (Primary/Secondary education) as there are some very slight differences in product changes depending on this.
You can opt here to move users from 'Rapid' to 'Scheduled' release of new features, giving you as an administrator time to train staff or alert them of upcoming changes. We'd recommend keeping this on rapid as any changes are normally very intuitive.
We would recommend reviewing and accepting both the Data Processing Ammendment and EU Model Contract Clauses. These establish Google's contractual obligation with you as a Data processor.
In this section you can upload a school logo which will replace the Google logo across your G Suite Apps such as Drive, Gmail and Calendar.
This section contains a plethora of information regarding security, data processing and privacy. These are great documents to share if you ever need to reassure a stakeholder who has trust concerns about using G Suite
You should enter the details of the relevant staff member in these fields in order to comply with GDPR.