Hi. here i am gonna explain to you about painting by "paint tool sai 2". At first you should buy this software frome here...
https://www.systemax.jp/en/sai/
version 1 is free but version 2 is not and the way that i want to teach you needs version 2. i love it because Working with the tools of this software is very simple and includes a few special tools that make design easier for those who are not professional. for more information read this...
https://en.wikipedia.org/wiki/Paint_Tool_SAI
The noteworthy thing about this software is that you can design without using pen tablet and just by having a mouse and keyboard. the most important tool for me is "curve". by that you can draw anything that you want like this...
In the next post, I'll tell you how to work with tools. bye for now