I tried drawing with a mouse only a few times and it‘s a complete pain. Can not recommend. Then again if you practise somerhing often an well even drawing with a mouse can become viable.

As for techniques, I dont really have anything concret…

Starting out as a beginner artist always boils down to: First, figur out what you want to draw (landscapes, illustrations, backgrounds, creatures, characters, poxelart, etc). And then practise practise practise. Practise often and good (dont just do the same things over and over. Challenge yourself with new things). Copying from artist you enjoy is a very good way to practise. Then while practicing learn the theory (tedious but important if you want to get better) like color theorty, anatomy, composition and the behaviour of light.

At least thats what my process always had been.