Go to east of Jublife City,then go to the cave continue to right. You arrive the oreburgh city. To access the 1st gym,you need to go to oreburgh mine and search for Roark(1st gym leader).Talk to him and finally,you can access to 1st gym.
by beating the gym leader
the first gym leader is roark. you have to go to the oreburg mine so that u can get the first badge in order to get hm 06 rock smash.
You can use the GTS in Pokemon Platinum after you get the first gym badge from the Oreburgh City gym.
go catch Giratina and then go to the Sunshore City gym and fight the gym leader
In Pokemon Diamond\Pearl, you go to the Veilstone City Gym. In Pokemon Platinum, you go to the Hearthome City Gym.
you go into the cave to oreburg and a hiker will give you it but you have to beat the gym leader first to use it
Go to pastoria and battle the gym leader wake
The fourth gym in platinum is the veilstone gym
You go on to defeat the eight gym leader.
to veilstone city
in snowpoint city
Go beat the fourth