Start slow and read the documentation.
It is very hard to say all in one topic, normally you should ask a single question about a specific issue then if someone knows the answer, you will get it.
But in general, you can use mach3 to control a plasma unit (I do), so with more or less changes one your machine you will be able to use it.
If that driver is not suitable for step direction signals, you can buy new drivers. They are not so expensive.
Filipe