How to use express keys?

I have a Huion h640 tablet. Is there an option to use the express keys?

@LunaticCimera You could probably map express keys to a specific shortcut combination and in turn to most functions in Pencil2D, however as far as i know you can’t map the express keys directly through the software. Not even with wacom tablets which have a wider support. What I used to do was exactly that, just map the specific command to a shortcut and then map the shortcut to the express key.