Exactly at 5:37 minute of that video (same person as the first tutorial) I was able to figure out how to solve my problem:
https://www.youtube.com/watch?v=0CPFt_vEqfk&list=PLnwVxZ2WVVpl1sOPaEzK--4fXzq2ZQvE-&index=49
I realized that to call the function he first called the variable (get variable):
But no use, if I do not know the correct type of variable (as you can see in the image above, circled in pink).
Only write Material Instance when defining the variable type:
Of the 7 options I tested option 4 and option 7. The correct one is option 7 (circled in pink in the image above).
To deduce that this option was correct, I had to see the 5:40 moment of the video (https://www.youtube.com/watch?v=0CPFt_vEqfk&list=PLnwVxZ2WVVpl1sOPaEzK--4fXzq2ZQvE-&index=49):
Step by step:
Important addition.
For the color to be set correctly, you need to set this variable first.
Just add this code to the Contruction Script:




