I used ibis with my finger for a while, it works just as well! There should be some tutorials you can find, but I’ll give you some tips!
ALWAYS USE LAYERS.
Like, color on a lower layer than your library. It looks cleaner that way.
THE BUCKET TOOL IS YOUR FRIEND
If you need to color a large area, the bucket tool is the place to be! Just make sure it’s fully closed off with no gaps.
When you go into the layer menu, there should be an option to make your layer a clipping layer. It basically means that anything you draw on it will only go over the previous layer. It’s great for highlights and shadows!
At the bottom, there are two sliders, one for brush size and one for opacity. Opacity is useful when you need shadows to not be so dark, or for highlights!
USE DIFFERENT BRUSHES!
Using all one brush gives your art a feeling of flatness. Try using different brushes for depth and texture!
That’s how i got from this
The second one is using a base that’s not my own, it’s just for a coloring example