Simple version:
You have battlechips. You have three actions. You use a battlechip an action.
There's other stuff, but that's only for when the battlechips run out.
Welcome. I'm PA, official... uh... child-RP'er and absentminded genius?
And as for your confusion with the battle system, if you'd like I'll create a "training sim" in the Spam Can, basically doing a "Lolz, how du I batle? U use da Custom menu!" thing. You know, when Lan completely forgets how to netbattle at the start of each game and has to do a training sim? Kinda like that, but for the site.
Final note: There's not actually a custom menu in our battle system... XD
And that about covers it! Welcome!