Well I don't know how it works in DPPt, but in HGSS, you go to Cerulean City Pokémart, because there are no moving NPC's there. Save in front of that dude, and make sure Prof. Elm can say something about Kanto (answer K), Pokérus (answer P) and about evolving (answer E). Go to seed to time, pick a time, press generate, and then hit Search Elm. That's how you advance frames in HGSS and how you can check which delay you had hit.