I'm not sure if this is the right forum but here goes

Can I and how do I get the head of a half stack to work separately?

Half stack is a Randall RX120RH if it matters
Go to Guitar Gear & Accesories, I think.

Richwood Les Paul RE-135
Ibanez RG350DX
Takamine Dreadnought
Hohner Telecaster Copy
Epiphone Thunderbird-IV Pro
Crafter Cruiser bass
do you mean make sounds out of the head itself?
if so, then it will never work.