What is a drum map?
A drum map is a list of drum sounds, with a number of settings for each sound. When you play back a MIDI track for which you have selected a drum map, the MIDI notes are filtered through the drum map before they are sent to the MIDI instrument.
How do I install Cubase drum maps?
In the Track Controls Settings window, select the MIDI tab. Then select Drum Map from the left side and add it to the list of visible controls on the right. Do the same thing on the Instrument tab. Confirm with OK.