Display gridlines-again

I tried the python code in the link and found that there seemed to be a grid in the three views below, but the main picture still did not show the grid I wanted. Also, I would like to ask how to add mesh customization for Slicermorpho?
I have looked at the tutorial of this link, it seems that I did not play a big role, there is still no grid line in the main view, I also want to achieve the similar effect of the video in the figure, may I ask what went wrong in the operation?
In addition, I import stl format data.

@ Tina_Kapur

Operating system:
Slicer version:5.6.1
Expected behavior:
Actual behavior: