I'm not sure if I understand what you are asking, but I don't think the calculations are really posted anywhere on the site. They are in the program though, so you might be able to work them out from the programming syntax.
If you go to the "Functions" tab in the Arduino IDE and then find the "FindHeliostatAltAndAz" function, you will find where the calculations are for calculating the heliostat coordinates. It basically inputs the sun's altitude and azimuth and the desired target altitude and azimuth and outputs the altitude and azimuth direction for the heliostat.
Is that what you are looking for?