description of features

Largely this is just done by selecting a given feature (by search or recent usage) from the list of features on the left hand side of the editor. The main description of a feature is through one or more tags, for instance to say something is a building the combination is a single tag building=yes, but if it's a stone building then building=yes, material=stone, if it's a stone school building with a tiled-roof then building=school, material=stone, roof:material=tiles

This whole approach means that you can provide the simplest information possible in a first pass and then add increasing amounts of detail.