At each of the places in Battle Frontier. Defeat the leaders of the places to get a battle symbol. Such as Battle Factory, Battle Dome and the others. Just beat the leaders of each facility and they'll give you a battle symbol.
yes
you have to get these symbols it's fun but hard
If you speak to Scott (the manager of the Battle Frontier) he will reward you with exclusive Berries.
battle fronteir is a place where you get to go after you beat the champion and you can battle there and win battle points to trade out or you can win symbols and battle points. you cant trade your symbols
Your Trainer Card will change color.
Better is pokemon emerald.you can catch more pokemon-you can catch kyogre and groudon-you can battle with the frontier brains and collect the seven symbols in battle frontier
Talk to Scott to receive a special berry.
4D2A5A81 4E69A107 Battle Frontier
Get all of gold symbols from Battle frontier.
You get a Symbol by beating one of the Frontier Brains, the bosses of the different facilities at the Battle Frontier. Once you win enough battles in a certain facility, the Frontier Brain there will challenge you. If you win the battle, you will get a Silver Symbol. Beat that Frontier Brain again and you get a Gold Symbol. You can get two Symbols (silver & gold) for each of the facilities in the Battle Frontier.
You can get the starf berry by talking to Scott after you earn all gold symbols (which is very VERY hard) from The Battle frontier.
if you fully beat it (all 7 gold symbols) and talk to scott he will give you a starf berry