Gee, Jeff why don't you tell us how you REALLY feel!
Here are some facts:
MACH is being used by over 15,000 customers.
There is a detailed manual at www.machsupport.com
MACH is a general purpose software controller used for router, plasma, lathe, foam cutting and many other multi axis projects. You can't draw with it, define toolpaths or generate G-Code. It's made to run the machine...period.
The integrator (OEM) that put your machine together and provided the MACH can (should) have a custom screen set (What you see on the screen) for your specific application (see my custom screens below we ship with our Plasma electronics).
The default screens have everything you might want So they are cluttered. The nice thing about MACH is it's extreme flexibility. It has more options than you will ever need in plasma cutting. It has a custom screen "Painter" that any OEM can use to make the interface be anything you want. Our screens will be different because we have the THC integrated into MACH and take advantage of MACH's built in THC logic and interface.
If you are expecting the MACH manual to teach you how to use your machine for Plasma CNC you will be disappointed. Once again it's up to the company that built the table to give you the information. MACH is a tool that can be used hundreds of ways
There is a very active Yahoo Forum (MACH1MACH2CNC) where the actual developer(s) hang out plus hundreds of other uses (a lot that use Plasma). You can get help there. The other source might be the person/company that made the interface controls. We support our products even after they are on a machine built by someone else. My support site is yahoo group CandCNCSupport. If your table has my controls (CandCNC) then join the group and get specific help on how to cut with plasma on a CNC.
I also might suggest if you want help you might not start out telling the person you need help from how ugly their baby is.