Kingdom Hearts 3D: Dream Drop Distance/Tutorial

This short chapter is essentially a tutorial. It is by far the simplest world. After some cutscenes, you can either watch some tutorials or go straight into the action.

Boss: Ursula
Before the fight, you can choose to play a Memento on combat basics. After the game instructs you to move the camera and Sora, you can begin your first attack. A tentacle will have made its way right in front of Sora's raft; attack it with until it falls back. After this, Ursula will begin her own attack by launching bubbles from her tentacles. Sora can either dodge or block these. Finally, lock onto one of her tentacles with   and blast it with a spell (Blizzard or Fire) from the Command Deck with ; repeat this for all tentacles until none remain. They will continue to launch bubbles at Sora as he attacks, so keep on the move between attacks to avoid getting hit. This completes the tutorial; now Riku will join Sora on the raft for the real fight.

Lock on to her face and begin the assault. Ursula will usually shoot lasers from her mouth, but can also summon thunder from above. Use a Potion when Sora's health drops too low. Eventually, the raft will be blown back, in which case Ursula can only be attacked using the two ranged spells in your deck. You can also choose to wait this out. Simply dodge Ursula's bubble and thunder attacks and you will be brought back with a violent swipe. Continue to use potions when necessary and hack away to complete the battle and increase Sora's Max HP.