If you battled Jupiter already, you have to go to mt. cornet and then go to the top to battle them and Cyrus.
Help the little girl and defeat commander mars.
beat mars in valley windworks
the next time you see commander mars is at stark mountain
To get to Snowpoint City you have to beat the Canalave City Gym Leader and then your rival will rush up to you and take you to the the top floor of the library. Professor Rowan will blab on about legendary Pokemon and stuff, and tell you to go to lake Valor. Beat the Team Galactic Grunt team members there then go to Lake Verity and beat Galactic Commander, Mars. Then Professor Rowan will ask you to up to Snowpoint City because he is worried about your rival. To get there you take Mt Coronet Path upwards from Celestic Town left route.
You go to Mt. cornet and capture Palkia/Dialga, you also must battle Syrus, Commander Mars and Commander Jupiter on the mountains peak.
You have to head off to Snowpoint City by going through Mt. Coronet.
with empoleon ,infernape and torterra
level your Pokemon up to 80
on Pokemon platinum mars and Jupiter plus charon is in stark mountain ok
You have to beat all the team Galactic Grunts, then your rival will show up and you two will have a tag battle with Commander Jupiter and Mars, then you get to fight the boss who has Pokemon around level 47, and the boss has already pulled Dialga out of it's dimension. Dialga wants to test you, and then, IT'S ON!
go tospear pillarafter rescuing the lake Pokemon before you get to dialga you must beat mars, Jupiter and the head of the team galactic the you will be able to battle him
You can get your Dialga by first beating the Pokemon League. Then, you go to Mount Coronet and there's like some kind of puzzle there, and you have to solve it. But you have to battle Commander Jupiter and Commander Mars, but your friend is there to help you. Then, you HAVE to beat the boss of Team Galactic, Cyrus! After you do, you battle Dialga, but just catch it with a Master Ball that Cyrus gave you in the Team Galactic Headquarters.
Go to Lake Verity. When you enter, Prof. Rowan will be there next to a Galactic Grunt. He'll say to go help Dawn/ the dude (I don't know his name. Sorry.) Anyway, you'll have to get passed 4 Grunts then commander Mars should be there. Defeat her and go to Acuity Lake and she will be there.
you need to beat commander mars first. after a battle the scientist wll tell you there is a balloon Pokemon that always come. drifloon always came every Friday. hope it help!
you have to go up mt. coronet but not through it you need strength and rock smash go to the top you will see lots of team galactic at the top you will see commander mars and commander jupiter they will double battle against you and your friend beat them your friend will heal your pokemon you will battle cyrus when you beat him go up to palkia and press a then catch him with the master ball then get the item behind him hope this helps
after the eterna city gym battle go to the Galactic Hq in eterna and beat Commander Mars. After get a bike after go get a underground kit. Then go to cycling road and a Dawn/Lucas's dad will give you it until you reached a certain amount of Pokemon in your pokedex
After you get the Master Ball from Cyrus, go to Mt. Coronet and into Spear Pillar. After you and your rival beat Commander Mars and Jupiter, Cyrus will Summon Dialga. Then Uxie, Mesprit, and Azelf will come to stop Dialga. Then Cyrus challenges you to a battle. After you beat Cyrus, you can try to catch Dialga.