You have see to many different pokemons. Then you will fill it (you have to every Pokemon to get national pokedex).
you just have to play the game
Capture all pokemons.
no they don't add Pokemon into your pokedex there
You fill the national dex by seeing or obtaining all 493 Pokemon. Some Pokemon don't count since you can only get them through events. (Palkia, Dialga, Giratini, Shaymin, Darkri, & Arceus) The best ways to fill the national dex is to migrate Pokemon, use the safari zone, use Hoen and Sinnoh sound, (If you don't know what this is, check out serenii.net.) and migrate Pokemon from the older games. You can also trade Pokemon From soulsilver to heartgold to get Pokemon unobtianable in soulsilver. (ex. Kyogre/Rayquaza) You can also trade with Pokemon Diamond Pearl and Platinum to help with th sinnoh part of the national dex.
You just get on with the game but go to the professor incase
Yes you can. You just have to fill up your pokedex and talk to pr.Rowan.
see every Pokemon in the reigon that the game takes place in. for the national dex, trade and migrate.
no
you got to migrate and trade from other Pokemon games or talk to dawns sisters and the Pokemon manchine owner and the will have talked about Pokemon that is not in the region you is in
yes you have to migrate
Fill up your Sinnoh pokedex. Here's something that will help you: Rotom.