You will learn to use brushes, masks, and polygroups, as well as the Best Preview Render (BPR) filter to achieve a 2D illustration aesthetic in 3D.
While I cannot provide a free link, here is how you can access the course and support the instructor:
While "Artistic Cartoon-Style Character Modeling with ZBrush" is a paid course, there are legitimate ways to access its content for free or at a lower cost, depending on your circumstances and needs.
: Use spheres for friendliness, squares for stability, and triangles for malice or speed.