You catch Regigigas by migrating Regirock, Regice, and Registeel from a GBA game then go to the Snowpoint temple in Snowpoint city.
you cannot catch the 3 regi's in Pokemon platinum you have to catch them in Pokemon emerald then transfer them to Pokemon platinum. thnx
you cant catch it in platnium but you can trade it
you cant
Yes you can.
no
no ditto is there
you get it from a fossil
Catch a wild magby
You can't you would have to catch one in Pokemon Heartgold or Pokemon Soulsilver and trade it to Platnium
No, you'll have to trade it from Platnium. Which in Platnium you find it in the Rock Peak Ruins.
top of mt cornet
you continue on to the next gym