A drum map consists of settings for 128 drum sounds, one for each MIDI note number.
To get an overview of the drum map settings, open the Drum Editor, and use the Map pop-up menu below the drum sound list to select the GM Map drum map.
The GM map is set up according to the General MIDI standard.
You can change all drum map settings, aside from the pitch, in the drum sound list or in the Drum Map Setup dialog. These changes affect all tracks that use the drum map.