you have 2 go 2 the peak of mount coronet but there r instructions on a website just type in HOW DO I GET TO THE PEAK OF MOUNT CORONET ON POKEMON DIAMOND FOR DS and it will tell you how
After you defeat Cyrus at the spear pillar, you can go to the lakes and defeat Uxie, Azelf and Mesprit.
after you get galactic key go to the HQ with sattilite dish go to the door
frst defeat the gym leaderthen go to the team galactic headquarters the one that is small. then when you have accomplished that you can go there!
you go to the headquarters in veilstone
Battle them. If they don't battle go another way.
Go to the Team Galactic HQ in Veilstone city
After you defeat Team Galactic, you go to Mt. Coronet and climb to the top. There, you'll have to defeat a couple of commanders and Cyrus again. Afterward, you'll get to face off with Palkia.
Go on to defeat team galactic
you go to mt.coronet and climb to the top battling grunts on the way
After you defeat their boss one last time they just go away. :P
after defeating commander Saturn at Lake Valour, you have to go to Lake Verity, fight four galactic grunts and then commander Mars.
go to jubilife and go up to floaroma city and defeat team galactic