the way i understand the game is this: you can see the lightning icon on the bottom, lets call it your energy gauge, you need a full energy gauge to perform an attack (left click) and a block (right click). everytime you perform an action you will empty said energy gauge and have to wait for it to fill up again, or you can fill it instantly by picking up the stocks that appear on screen.
the enemies have two types of attacks, lets call them normal and strong. you can block the normal ones, wich are represented by a circle. to perform a block correctly you have to time it when that circle almost fills up.
you cannot block the strong ones, you have to avoid them, and that is as simple as moving the cursor out of the red zone.
and thats pretty much it, sorry if my english was bad, im still working on it