I don't understand the battling system

[Marisaur]

I'm new, obviously. and I went to the battle arena. I don't have any items or what ever, so I used my bare fists, and it never did anything. Help?

[Pikmin]

Bare fists have such an annoying habit of missing, your best bet is to buy a volleyball from here, as you'll hit a lot more, and it has a lot of durability, as well as being cheap...
When you're in battle you can then switch to it on the drop down menu that has bare fists normally, it doesn't need to be equipped beforehand..
(and personally I've never used any of the armour that does need to be equipped pre-fight xD)
Also fighters tend to be waaay the easiest class here to use.

[Maeve]

As Kupsy said, bare fists have very little chance to hit, and even when they do, they do very little damage. You can get a volleyball from the weaponsmith shop, which is pretty much the best weapon for a newbie.

I guess I could go on and on and try to explain a lot of other things, but I've already written them in the Newcomers Help Center (linked in my signature), so I'd suggest visiting it first; and if you have any question left, just ask! ^^