Intro and Beginners

I'm a re-newcomer to lathes and mills. As I grew up, there were
always lathes and mills around. My dad was a tool & die maker
by trade, so it's always been around me.

Well, it's been a while, and it's been nipping at my heels, so I'm
splurging and buying equipment.

Still some things I need to understand in the computerized and CNC
world of machining.

I understand how the CNC works, and the principles. I just have
a hard time understanding how you start, ie, tell the software that
the slide is here, the tool is angled this way, etc... you know: the
EXACT position of the tool in relation to the material, so it knows
how/where to move it.

How is this set up? Lord knows the tool can be mounted in a bazillion
different ways!

Am I phrasing the question correctly?


Tony