Basic g-code commands

I seem to have my sherline cnc mill working fine. I am still in the
process of teaching myself cad/cam. In the meantime I would still
like to work on my model steam engine that I started before the CNC
conversion. The problem is I am not sure of the basic codes used to
just make a cut. I am using Turbocnc, and can jog just fine but
having it say make a say a 1.5 inch pass on the y-axis is kind of
confusing me. I guess I am just looking for basic commands that
would replace the cranking on the handwheels I did before the
conversion. As Always, thanks for the help.

Matt