How do you pass through team aqua guards

ok first you have to get to lilycove (which you should be if your asking) go to slateport city then act like your going to the cycling road but just before the route you should see a lot of people by captin stern talk to him and he is getting interviewed then team aqua steals a submarine go back to lilycove and go to the hide out then you should be able to go through. PS grab the master ball in there if you dont its gone for ever