Learning Autocad

If you want to learn acad as a means to a job where you would be
working as a mechanical draftsperson, then you're on the right track.
If you want to design things for cnc, then I'd start from scratch with
(my particular choice, others have other opinions) Vector cad/cam. You
can get a deal on vector cad, I think, then put out the few more bucks
for the cam functions.

This will get you something that is efficient for making cnc parts from
the beginning, rather than making drawings that have to be massaged
in order to even think about making parts.

Other options abound.
acad is also not cheap, and they have a bounty program for cheaters.
/mark