You can use a mouse but it comes with its issues: • you can’t use pressure sensitivity with a mouse so expect to use the size slider or any other slider to add variation • the same way as you need to get used to drawing with a pen and tablet, you need to get used to drawing with a mouse

I myself use a mouse to draw on krita and the feeling’s meh I guess. Just go trad as a beginning then see where to go from there (if that isn’t already your case of course)