Suggest you try CAMBAM for an all-round CAM program for 2D, 2.5D and 3D. Bit of a steep learning curve, but the forum is top notch. One contributor took the CAMBAM help files and translated them into a PDF. Suggest you print the PDF in color as much of the info to be gleaned comes easily from the colored diagrams.

As for MACH3. Though is a lot of pages [350..I think], print out the whole MACH3 manual. [Do it on a laser jet printer, not on an ink-jet printer; laser is faster and better quality, plus less expensive!] I found it is easier to really learn MACH3 when I could write notes in the margins as I read; plus using the usual amount of sticky notes.

Oh, buy a package of paper [ream...500 sheets] that is already punched for a 3-ring binder [they have it at Staples]. Save you lots of grief in both having these two documents always organized...and not having to punch holes with a 3-hole punch!