You dont
sinnoh Pokemon won't appear in Sapphire version!
No there is no way to get to Sinnoh.
By buying a specially marked version of Black 2 or White 2 from participating Walmart stores.
There is no kanto champion. But there is sinnoh champion Cynthia at undella bay
Garatina...
You cant.
Spiritomb
In Diamond & Pearl's version of the Sinnoh Dex, Pokémon #149 is Dialga.
You can't go to Sinnoh in the Gen V games.
Munchlax is a Sinnoh region Pokemon, which when Pokemon Sapphire, Ruby, and Emerald were released, Sinnoh did not exist yet. It is unobtainable in the three games.
You can't. After beating N at his castle and obtaining the National Dex, you can catch Pokemon from Sinnoh.
In Pokemon Platinum Version, there are two Pokedex'es, the Sinnoh Dex, and the National Dex. In the Sinnoh Dex, the 151 Pokemon is Manaphy. In the National Dex, the 151 Pokemon is Mew.