you don't, you get it as a starter from professor oak after beating Red
You can't catch bastiodon in Pokemon soulsilver.
check your pokedex and it is only available to catch in you chose charamander as your starter pokemon.
catch it? no.
No, you can not catch Phanpy in SoulSilver. It is a version exclusive to HeartGold.
You cannot catch Heatran in Pokémon SoulSilver, you will have to trade for it.
You cannot catch Celebi in Pokemon Soulsilver, you have to transfer it from Diamond and Pearl (if you have it in those games).
No.
No.
you trade
You can use any type of Poke Ball that you want to catch Spheal in Pokemon SoulSilver.
there is a mew in Pokemon soulsilver but you need to catch all leadndery Pokemon including event Pokemon
You can't catch a piplup in soulsilver