How to Draw Anime & Manga (Free) by Sergey Burlakov is intended to show you how to draw anime and manga cartoons by giving step by step instructions on around 20 cartoons.
Each step builds on the previous step and shows a wire frame around which the image is being drawn. The images grow in detail and complexity until you reach the final image which is the complete cartoon.
Deconstructed cartoons are very easy to follow and show how to use geometric shapes to set the dimensions of what you want to draw.
Presumably, one can then take what’s been learned and apply it to any picture one may want to draw. I don’t know how easy a transition that would be — I’d imagine it would take some talent to start with.
There are no written instructions nor is any indication given on how to best draw the cartoons on a computer although the app seems aimed at those who use a pencil and paper. The point is, this app will never be a replacement for a proper educational course on art.
However, if drawing is a hobby of yours and you would like to expand your repertoire into anime and manga, this app will provide a fun start. See the images below for my attempt at drawing the first cartoon: Anime Girl.