With two days to go in the PlayStation All-Stars Battle Royale beta the game's developer, SuperBot Entertainment, has released this video covering the basics of the game. It's an attempt to answer a lot of the questions the studio has been fielding since the beta opened on October 16, but it also functions as a video tutorial for the main game.
The video underlines the importance of blocking (and learning how to throw, to defeat blocks). Dodging and air dodge also seem to be important moves to deploy. If you see special items, use R1, that picks them up and activates them.