Understanding cnc lathe programming?

Once upon a time I was the principle cnc programmer and operator for a
cabinetry company. I learned to master it quickly. I have just
retrofitted a lathe and have no idea what type of drawing files to
import into programming software. Do I have to draw 3d drawings of the
part? Can I just draw one half of the part which would just be the
toolpath? Do I have to draw the material lines, then the lines cut
within that meterial? Just trying to figure out the new toy. I am using
mach 3 and their lazy cam software. www.artsoft.com I think is their
site. Any advice would be great.
Jeff
Van Nuys, CA