Bit more detail on what is causing you problems might help, from what I can see the machine comes complete so just a need to install software & set that up, Mach3 is quite easy to set up but if you are having problems there are some support videos that explain further as well as the manual. Lazycam which is used to create your g code doesn't have a lot of support so might cause you a problem or two & G simple I've never heard of sorry. Sounds like it's another cam program so you may also need some software to do your design work with, something that will export a DXF file that you can then import into the cam package.

What operating system are you running on the computer & are you running 32 or 64 bit?