How do you the dongle method on pearl?

First u must finish elite four, get the whole sinnoh dex except for Manaphy. Then you must go to the professors office and talk to him. Another professor will walk in and upgrade your dex to National Mode. He will then tell you about Pal Park. Go to Pal Park (you just need to go there, you don't have to actually use it.) then save and put GBA game in and yurn of power. THen you can go to certain places and depending on what GBA u use different Pokemon appear.

u can check what Pokemon u get and where on bulbapedia.