use action replay
You have see to many different pokemons. Then you will fill it (you have to every Pokemon to get national pokedex).
Yes you can. You just have to fill up your pokedex and talk to pr.Rowan.
you just have to play the game
Fill up your Sinnoh pokedex. Here's something that will help you: Rotom.
no they don't add Pokemon into your pokedex there
In the National Pokedex, it is Tentacool. Should be the same for Platinum.
there is no number 211 in platinum pokedex. no. 211 in national pokedex is Quilfish.
complete the normal pokedex
No.
You do not need the national pokedex in platinum, simply talk to Bebe in Hearthome city
To get the Poke Radar you gotta fill up the Sinnoh Pokedex, talk to the professor, and he will give you the National Pokedex and the Poke Radar.
First you bet all of the gym leaders and the elite 4, then you fill up the Sinnoh pokedeck. After that you talk to Professior Rowan, and get the national pokedex. Then you bet the new team glatic master, and fill up the national pokedex