When I was starting to learn on Paint Tool Sai I had already some basic knowledge of photoshop. Enough that I could ink and color a little better than a beginner. So as Paint Tool Sai is similar in many ways I when to YouTube to seek some knowledge on how to work with this software.
And there is no end to helpful videos on there.
Video by Soreiya
If you like this video, then I hope you go and check the artist youtube channel.
When you show them your love of their work, then that makes them want to create even more awesome material. And that is a simple win-win.
On til next time. <3 <3 <3