I can't tell you everything here, but you have to go to One Island and get the Ruby. Then you give it to Bill, who is in the One Island PC. He will upgrade your pass and you can go to Four Island, Five and six and seven Island. You have to get the sapphire on the Six Island. Give it to Bill and he will successfully upgrade the trading system. Now you can trade between the Sapphire and Ruby and Emerald Versions. You can just now enjoy and explore the Islands. If you have more questions, go to
www.pokemongames.com. There you will find guides and cheats, find what you want to know and follow the guide/cheat. I am playing Firered version too! Hope you can find the Islands.