How do you catch Rayquazza Groudon and Kyogre on pokemon soul silver?

After you've defeated Red (meaning you've also collected all 16 badges and beaten the revamped Elite Four) Professor Oak will give you a choice of one of three of the Kanto starters. Now go see Mr. Pokemon in Johto. He will give you the Red Orb. Take it to Route 47 and enter the Embedded Tower. For SoulSilver, you can catch Groudon here. Kyogre can only be obtained via this method but in HeartGold. Then, transfer both Pokemon to one game and bring them to Professor Oak. He will give you the Jade Orb, and return with it to the Embedded Tower to catch Rayquaza. You need to have a Groudon caught in SoulSilver and a Kyogre from HeartGold (that is, not transferred from Emerald, Ruby, Sapphire, etc).