Hi Johnson, your question is very general, any particular programing you prefer? Or what particular activity would you wish to program the CNC to carry out? 

You have the option of G or M-code. Therefore, you have to specify which one you wish to use. 

For G-code, i would say all you need is the chart indicating the sequence that will be executed by the particular instructions. I find it easier or more likeable compared to M-code. 

Am also a G-code fan. All you need here is the chart showing the codes to use. Once you enter the right code on your CNC machine, it will handle the rest. 

But first you will need to determine the machining operations that you wish to carry out on your CNC. Simple machining doesn't require complicated codes, but sometimes you can get complex drawings with multiple views.