please help

To get Dialga and Palkia on Platinum, you have to have beaten the Pokemon Leauge, and in Mt. Coronet, on your way to Spear Pillar, there is a door in the snow area that is right next to the spot where you use Rock Climb, go into that room, and there should be a place to surf, and then a waterfall, go up the water fall and you should come to a room, go in that room, in the room there should be 2 pokeballs and a rock, the first pokeball is the Admant Orb, the second pokeball is the lustreous orb, and the rock has an invisible item, it is the Stone Plate. After you get the orbs, continue to Spear Pillar where the first time you go in, at the back of it, there should either be a blue or pink time rip..blue is dialga, pink is palkia, there is only one at a time..press A on the time rip to battle them..after you battle the first one, go out of spear piller back into the cave then go back in and battle the other. Hope I could help ~magicplayer12

The cave with the waterfall in mount cordanant in the cave you will find the adament & lustorius orbs

You need to get the Adamant and Lutorus Orbs from inside Mount Coronet they are in a cave at the top of the waterfall about Half way up the mountain.

You need:

Adamant Orb
Lustrous Orb

Here's what you do:

Go to the Pokemon League and win.
Fly to Canalave City.
Talk to Lucian on the first floor of the Library.
Read the book titled: The Original Story.
Go back to Spear Pillar and they should be there, if you know what to do to get Palkia there. You beat Dialga and then go in and out of Mt. Coronet and his rift should be there.

Use a quick at first