OMG! I can't believe you guys never played one of the best Mario games ever! And you claim to be Mario fans... jk jk Well.. the battle system is is turn based. Either you or the enemies select your/their moves/items and use them.. then the opposing side takes a turn. As for the game outside of battle, you just walk around, and if you touch a baddie, then you fight them. =)
*You quickly shove bananas in your ears.