Mainly for me but I hope others can get some use out of it, I use a mouse to draw plus I'm left-handed (I've always used mice with my right hand) drawing with a mouse is hard for me especially because I'm either using my non-dominant hand or the hand I've never really used a mouse with. If I practice with my left hand it can (in theory) become easier to use the mouse with than my right but currently, my right hand is easier. This is to help me (and any others) practice drawing with a mouse and/or with my left hand and/or any other forms of digital art. I hope you find this helpful!
Instructions:
For the shapes~ It's pretty intuitive just draw the shapes as best as you can over the dotted lines like how you practiced writing letters on those things in kindergarten (anyone else remember that?) do so on the extra layer so you can erase it or alternatively make a new layer each time hiding the old ones so you can see how they improve!
Red dots~ draw a line from one black dot to the other weaving between the red dots, for varying difficulties hide and show the different layers to make more dots closer together, when doing this keep in mind that the system works so you have to have multiple layers visible at once
Ex:
Difficulty 1 ~ 1st layer
Difficulty 2 ~ 1st 2 layers
Difficulty 3 ~ all 3 red dot layers
of course, you can change it up a bit for varying dot distances if you'd like and I'd also recommend switching the direction of your line for more variety
I struggle to not write too much so you might want to skim the instructions
hope this helps you <3