Things You'll Need
Instructions
Insert "Pokemon FireRed" or "Pokemon LeafGreen" into the Nintendo DS. Load the "FireRed" or "LeafGreen" save file.
Travel to any PokeCenter and place Articuno in the Pokemon Storage System. Save your progress.
Go to the "Pokemon Diamond" main menu. Select "Migrate From FireRed" or "Migrate From LeafGreen." Select six Pokemon, including the Articuno, from your Pokemon Storage System.
Continue "Pokemon Diamond" from your last save point. Spot all 150 Pokemon in the Sinnoh region and speak to Professor Rowan to get your National Pokedex.
Surf southeast from Sandgem Town to reach Route 221. Enter the Pal Park facility on Route 221. Speak to the man who is wearing a hat. Select "Enter" from the small drop-down menu. The man will give you six Park Balls and allow you to enter the catching grounds.
Look for Articuno in the mountainous section of Pal Park. Catch it with a Park Ball. Capture the remaining five Pokemon in Pal Park to end the game. Retrieve Articuno from the Pokemon Storage System.