Your school needs to adopt the ICO's model publication scheme
All public authorities, including schools, are required under the Freedom of Information Act to adopt a publication scheme that has been approved by the Information Commissioner's Office (ICO).
Your school must adopt the ICO’s model scheme and make it publicly available – e.g. by linking to it on its website (see the section 'where to publish the scheme and guide to information' below). Your school doesn't need to edit the scheme in any way.
You'll also find the requirements for publication schemes in the ICO's guidance 'model publication scheme – using the definition documents' (pages 2 to 3). This is can be found in the section 'what kind of information should we publish and include in our guide