In that case use these steps per Serebii.net:
#382 Kyogre & #383 Groudon
Kyogre & Groudon are both available within this game. To access them, you need to obtain the Blue Orb if in Heart Gold or the Red Orb if in Soul Silver. These orbs are found from Mr. Pokémon after you have obtained the National Dex and received the Kanto starters from Professor Oak. With these orbs in hand, you need to head to a cave in Route 47, the Embedded Tower. Traverse the cave and you will find Kyogre if you're playing Heart Gold or Groudon if you are playing Soul Silver. They are at Level 50 so be prepared. Unlike Lugia & Ho-Oh, you cannot get both Pokémon in one game so you'll have to trade to get both.