Follow the stops in order, from Twinleaf Town through the eight Gyms (in Platinum's order) to the post-game. It uses Platinum's Sinnoh Pokédex of 210; pick your version to see what you can catch. Each Pokémon is listed at the first point you can reach a place where it appears; surfing, fishing and Rock Smash spots count from when you can use them, and Poké Radar and swarm Pokémon from the National Pokédex. Tap a row to check it off. Evolves into shows later stages and how they evolve.
National Pokédex: see every Pokémon in the Sinnoh Pokédex, then show Professor Rowan. It unlocks the Poké Radar, swarms and the post-game areas. There is no Shiny Charm in these games.
Legendary Pokémon
Sinnoh legendaries in the Pokédex are checked off together with it. The others appear in the post-game, some only in Platinum or through past events.