Hi Leonard,
There is a function called translation. Start with a known CS such as your MCS and using the translation function define where you want to move your X,Y and Z. If you want your axis to be at a different angle than the MCS, use rotation and define the angle you want.
Your other choice would be to go a more familiar route and key in your plane, set your base plane, key in your line set your axis, and key in your point for you origin.
Jeff