In which case we need more clarification.
Thinking about this I set the origin point in CAD at the point I want to start or top left which for me is the fixed point on my machine, left hand side of the fixed vise jaw.

Many use bottom left because then all moves up and right are positive but it doesn't matter to a CNC what is positive or negative.

I don't use bottom left because that's the moving jaw and if your blank material differs in depth, Y+, Y-, then the parts come out different.

Next step is CAM just uses this point.

However it's not something that's written in stone, like many machining operations there is never a laid down right way and wrong way, just different ways of doing things.