Assign VoiceOver commands on your Mac to braille display keys
VoiceOver detects whether your braille display provides input keys and assigns common VoiceOver commands to the keys. For example, VoiceOver might assign the Down command to the D3 key; when you press that key on your braille display, the VoiceOver cursor moves down one line on the screen.
Note: VO represents the VoiceOver modifier.
With your braille display connected to your Mac and with VoiceOver on, open VoiceOver Utility by pressing VO-F8.
Click the Braille category, click Displays, select the braille display you want to assign commands for, then click Assign Commands.
Assign a VoiceOver command to braille display keys.
Change the command assigned to keys: Navigate to the keys, click the pop-up menu, then choose a command.
Add new braille keys so you can assign a command to them: Click the Add button to add a row, press Command-B, then within 5 seconds press the braille keys you want to add. A sound effect counts down the seconds. Click the pop-up menu, then choose a command to assign to the keys.