you can't.. make sure you have the three regi's and migrate them to Pokemon diamond/ pearl. You need National Dex. Now enter the Snowtemple in Snowpoint City. Regigas will be waiting if you bring the 3 Regi's.
Finish Poked ex
Pokemon diamond
Pokemon diamond Pokemon diamond Pokemon diamond
you cant be a Pokemon in Pokemon diamond
She is not in Pokemon diamond.
There is no Pokemon temple! There is such thing as Pokemon diamond.
Pokemon 134 is Finneon in diamond
Chingling is the 47th Pokemon in Pokemon Diamond.
where are special key in Pokemon diamond where are special key in Pokemon diamond
You can not get dark Pokemon on Pokemon diamond and pearl
You need to transfer all three regies from either sapphire,ruby,or emerald.They are ice,rock,and some other one.When you transfer them to either diamond or pearl put all three in your party and go to the snowtemple.But first help the boy in Canalave city stop his nightmare.The lady at the snowtemple will deny you but then Candice comes and lets you in.Go all the way downstairs and regigigas is there in the middle of ice. (You need to have beaten the Pokemon league and received the National Dex) Good Luck!!