you go to sunyshore city and beat the gym leader
you can do about anything after you just cant beat the gym leaders again.
go to hearthome city
You have to beat the Gym Trainer Wake and he will give you surf. Then you have to surf there.
go catch Giratina and then go to the Sunshore City gym and fight the gym leader
beat the gym leaders
you beat the sixth gym
The 6th Gym Leader in Pokemon Platinum is Byron in Canalave City. He specializes in Steel-type Pokemon and has a Steel based Gym that looks like a construction site.
Surf from Jubilife city to Canalave (Left)
In Canalive City to the west of Jubilife city!
Go beat the fourth
beat gym leader Candice
umm...you beat the 7th gym
Go to the veilstone gym and beat maylene.
beat the heart home gym
you must beat the eighth gym leader and he will give you the badge.
beat Fantina in the hearthome city gym