It's complicated. You need the controls. And a steering wheel back with the cutout for the controls. And then a clock spring for a column that has the controls. Then you can extend the wires for the controls to your aftermarket head unit. I don't think it's worth it personally.
I bought an aftermarket kit way back for my 07 Focus that had a lever that attached to the steering wheel for adding controls without having to rip the wheel apart. Unfortunately, I cannot remember what it was called at all, but it might be an idea for you that is less work.