Hi: You are on the vertical potion of the learning curve. Pickup a basic CNC handbook (Peter Smid), and get the basics. Short of that, even with your manual machining skills, there is a very high probability that you will damage the machine, or worse, hurt yourself.
The fact that it freaks you out, tells me that you are nervous or uncomfortable with this, so build some confidence the safe way, get some demo software, have the re-seller give you 1 hour of the basics, and hit the books...
regards
----------------
Can't Fix Stupid