Go to the lake, which is nearby. Beat the guys. Then go to the team galactic HQ in veilstone. Take it from there
umm...you beat the 7th gym
beat the 8th gym
beat the gym leaders
Go beat the fourth
snowpoint city
beat gym leader Candice
beat the heart home gym
Go to the veilstone gym and beat maylene.
Get Kyogre..
you must beat the eighth gym leader and he will give you the badge.
When you beat the 7th gym leader and have seen everything at the lake you go to spear pillar at the top of MT. Cornet
beat Fantina in the hearthome city gym