As there is no reply to my question,, I've been trying to figure it out.. I've found the github INDI driver for the Rigel n-step focus motor and the INDI driver 'header' in Kstars INDI directory and confirms it appears it has no 'code' or script.
Can I copy and past the script in this github page (link below) into a Mac terminal window opened in the INDI directory and will it save and run? Hopefully its as simple as this. Or otherwise, how do you install this driver to Kstars Mac Indi directory? Currently the weather prevents me from just trying out this or other methods and other options.