Peter Brett outlines schedules on pages 39 - 43, he outlines their purpose and shows that they are used for:

Doors, Frames and Linings Windows and Ironmongery amongst other things

He also shows that there are three parts to a schedule a component range drawing, a floor plan and the schedule (grid) itself

From these, information such as component type, location, methods of fixing and finish can be gathered.

Floor Plan