How to use a mouse in game ??

[miochibana]

I don't understand anything, should I move the mouse with my hand or my arm? Should my wrist be stiff when moving with the arm? So, is there an official way to play with a mouse? On a controller it's simple everyone uses it the same way!! I'm lost and yet I've been playing keyboard and mouse for years, but I feel like I'm doing things wrong!