Hi! Im a complete beginner to Zbrush and just 3D in general. I wanna learn as much and as fast as possible so im trying to make the best out of this, but im not sure what order I should learn the fundamentals in since i’m so new to 3D (apart from a few low poly-blender models). I want to focus mostly on making realistic portraits, all I know is that I should start off by learning how to use the program. I’ve come from drawing so I know that you have to understand different fundamentals (form, color, etc) Sorry if this is an annoying beginner question!! I will make sure to do my own research as well on this 
Also any unrelated tips for someone just starting out are more than welcome!!