Well you could go to this website they have everything you need to know about Pokemon. (In my opinion)
www.serebii.net
First you need to be able to access the battle towers. You have to battle in one of the towers until they notice you are good at the game. A frontier brain will then battle you. Another website is,
Bulbapedia.bulbagarden.net/
I personally like it better then Serebii
beat the fronteir brain
You can get to the battle frontier after you beat the Elite Four
Smeargle.
No, because there is a battle fronteir in Emerald only.
battle fronteir
It is located in east of olivine city.
You can't
you have to go to the battle fronteir after you beat the game
the only way to get to the fronteir brain in the battle dome in pokemon emerald is by beating the battle dome 10 times the only way to get to the fronteir brain in the battle dome in pokemon emerald is by beating the battle dome 10 times
it is west of olivine city on route 40
You can get unlimited rare candys from the battle fronteir
Yes, in the Orange League and Battle Fronteir