>>529759908
As people have already mentioned dodging is your no. 1 (one, una) tool in melee: You should basically constantly be dodging to the sides while mashing MB1, and dodging backwards if you see some big wind-up shit coming down on you. Not everything can be dodged out of in this way though and that's where blocking becomes mandatory. You'll learn what to use and when in time.
And fucking disable the "doubletap directional button or jump for dodge" options if those are still on by default!