Do you mean guiding as in collecting an image of a star field, detecting any movement and issuing guide commands to a mount or working out conversions from a star position in Ra and Dec to motor axis positions and drive rates?
They are different problems, but both non-trivial.
There's another problem, to get star positions and send commands to an existing scope control system. It feels slightly easier but needs a star charting program to get the star positions. I'm not sure what is available, somebody managed to compile Stellarium but it may not have run very well.