The Schematron Open Documentation explains ISO Standard Schematron for users and investigators.
Open: It is intended as a community effort. If you have some material that might explain Schematron more clearly or more effectively for some users, please add your suggestions in comments. Graphics and alternatives to text are particularly welcome. It will be licensed under suitable conventions, probably the Creative Commons
Timetable: This documentation effort has started, and a first version is expected during 4Q 2021.
Status: This documentation is intended to complement the ISO/IEC international standard IS 19757-3:2020 and is not an alternative formal standard by a recognized standards body. All care will be taken to align with the international standard, however in no way should this documentation project be taken as an authoritative alternative text of the international standard. (Some national legislation preference technologies with free public documentation: the Schematron Open Document should satisfy that, though in every case the international standard should be preferred.)