go to spear pillar
You can't - yet
digla
you can but you need an arceus then go to the ruins of alph into the small lab and then you can get a giratina,digla, or palkia
If u already defeated digla then return to spear pillar and there will be stairs (or somting like that) at the back go to them and go down them it will be thereHOPE THIS HELPS! :)
they are the same.the only difffernce is there is palkia in pearl and digla in diamond i like diamond the best shieldon can be found only in pearl and cranidos can only be found in diamond same as misdreavius and murkrow
to use it you have to go to the place where you catch Digla,Palkia and Giratina. Once you stand on the trangle thing in the first place you use it and then u cna battle Aruces at lv.70 ( i think the event is over 0.o)
It is a couple missions after Angis cave. Then you have to travel 20 floors to find drowzee.
I suggest u catch a shiny Pokemon and trade it for a lv 100 palkia/digla
to got shaymin you have to first comepte the story mode by defeating primal digla that you must also have the 5 episodes in story mode done also then go to spinda cafe and they wil tell you about going to sky peak where there are 10 section in the game. beware you must also have some room in you party to have shaymi nin your group. after that you have 10 sections to go up to sky peak and once your done with that. go back to sky peak and see shaymin again and he will join you group.