You can't.
arceus is an event pokemon.
Pokemon Diamond, Pearl, and Platinum have Arceus.
You can only get Arceus by an Event.
you can catch arceus in Pokemon lake online at map 10 + 14 only if you have all 56 badges!!!!!!!!!
me
anywhere with a chance of 1 in 2,348
You can't catch Arceus. You can only catch Arceus in Pokemon Platinum.
Arceus.
Arceus
you can not get arceus with no action replay
You have to transfer from Pokemon Ranger: Shadows of Alima... hope that helps