Cure is one of the items that shows up in your upper-right screen when you're on the board moving to your next battle. You buy it with KP from the Moogle Shop or sometimes pick it up as an item on the board.
Potions show up on the board as blue bottles.
EX Mode is the meter on the left-hand side of the screen when you're in battle mode; when it's all the way full you can go into EX mode. (I think you hold down R and hit square to activate EX mode.) While in EX mode you'll regenerate HP (usually; some characters don't) but you become significantly more badass.
In general, you can open any part of the menu and hit--I think it's Start or Select to bring up the in-game manual, which might also have some information for you.
no subject
Potions show up on the board as blue bottles.
EX Mode is the meter on the left-hand side of the screen when you're in battle mode; when it's all the way full you can go into EX mode. (I think you hold down R and hit square to activate EX mode.) While in EX mode you'll regenerate HP (usually; some characters don't) but you become significantly more badass.
In general, you can open any part of the menu and hit--I think it's Start or Select to bring up the in-game manual, which might also have some information for you.