I find that I really have problems with seeing the planes on round objects. I realize this when drawing faces as well. I first watched the 6 minutes project video and then tried on my own from the photograph. After this drawing I did several value studies with different grade pencils to find the combination which best gives me two light and two dark values.
Unfortunately in Krita 5.1.0 things have changed a bit. The import of the brushes looks different and unfortunately I cannot find where to adjust the brushes/tools since a click on the icon on the top does not bring up the "most complicated window in Krita". An update of this video would be highly appreciated, Marco. Thank you.