Since the processing for documents, media and materials are similar, we will only describe the steps for the materials.
If you want to classify materials in the Global materials, go to Material (1.) and pick (2.) your selection of materials. Then you can click on Classify (3.).
Now a window with the filters opens. Define your structure class characteristics in the filter and click on Selection.
Filtering by using classifications
Now you can set the filter in the list of materials so that only the selected materials are displayed.