how to build a scratchpad like list type gen?

We have a powerful scratchpad that can assign variable like

    
CHARA = prompt.....
CHARB = prompt.....


  

We can also import list type gen like the demo {import:noun} not in code but direct in prompt area.

But that's way too simple and scattered around all places. How do we custom a more complicated list gen like I can do in scratchpad and import it directly in prompt textarea? Even still use custom variable like [CHARA], [CHARB], DESCRIPTION = ? using selectone.? output? $output? ??? I have absolutely no idea.

After checking the tutorial and it's still too hard for me...