How do you get to sevii islands

well you have to beat the 7th gym leader and then bill will appear and take you to the first 3. if you want to get to 4-7 you have to beat the elite four and have at least 60 Pokemon in your pokedex. once you do this talk to prof. oak and he will give you a national pokedex which is like an upgrade. when your done go back to one island and talk to the guy working on the machine. he will ask for a ruby. go to mt. ember which is just north and fight two team rocket members. go inside of the cave that they were by and get the ruby. after this talk to the guy working on the machine. he will ask for a sapphire and give you the pass to islands 4-7.