@JoeChen as @Rene_Poschl already pointed out there are some tutorial videos out there:
https://www.google.com/search?q=kicad+stepup#q=kicad+stepup&tbm=vid
import STEP model and align to kicad footprint
an other ksu alignment video
please note you don’t need to copy all demo folder files, just the kicad-StepUp-tools.FCMacro file
Now the ksu Gui has been improved and it is more compact… but the functionalities are the same or even better 