Cross - Movement ingame, in menus, when selecting options in conversations and when crafting. 2-times fast in one direction for sprint.
A - speaking to NPCs (Non-Player-Character), picking up stuff.
B - attack with current weapon, combo attack by using it several times, additional combo attacks are possible after archiving higher skilllevel with that weapon. (20+ for example), when used as Mokomoko (Wooly), the attack is bare-handed.
Y - Skill#1 (found right in menu, left on-screen)
X - Skill#2 (found left in menu, above on-screen)
L + B/Y/X - Short-menu, to choose stuff without calling up the menu.
R + Cross - Walking instead of running.
Skills can mean:
- Magic (healing, attack, teleport ~blue sphere~)
- Techniques (every weapon has several)
- Music notes (let's companions do something, ~never really used~

)
- Transformation, with the emblem skill (also known as transformation belt), which needs the knowledge of transformation, gained from clearing Spring/1. Dungeon.
Additionally the whole game can be controlled by Stylus/Touchscreen.
That should be about all.