Click on (Highlight) kit piece or Mixer Slot.
Click on Keymap…
To the Left of the kit view is the Keyboard View/Piano Roll…
To the Right of the kit view is the Slot/Name with the Articulation List below…
Click on (highlight) an articulation
Click on (highlight) the key/note you want in the piano roll
Below the Articulation List windows is the Map Editor…
You’ll see Selected Note and “Assign to Selected”…
Click on “Assign to Selected”…you’ll see the selected note value change and below it all the assignments to the key/note…
Below Assignments are for any adjustments you would like to make.
Make an error or remove assignment…to the right of the assignment is an X
Keyboard/Piano roll below kit window…click on the key/note,the articulation should sound and a popup window “Key” " contains…(the assigned articulation.)
You can also use follow MIDI if you have a MIDI controller or drum kit etc being used.
Don’t forget to save…
More info…
in BFD3
Help > Launch Online Manual > MIDI Key and Automation Mapping > MIDI key Maps