you can't unable
You just find it!
in rooms
spear pillar
On the last gym leaders map
You can find Regigigas in Snowpoint Temple in Pokemon Diamond, you will need to bring Regice, Registeel and Regirock for Regigigas to waken.
snowpoint temple
In Snowpoint Temple
you can catch regigigas in the snow point temple
you have to climb up mount Everest and then you see azelf and he pushes you down
Yes, it is. You can also join the best pokemonindigo clan. http:/final-legendaries.forumotion.com ;)
regigigas is not a Pokemon you can obtain in ruby because regigigas was made in diamond and pearl and platinum so you can't get it in ruby ever.
Regigigas was not made during the Emerald era, you can only get the 3 Regis. Regigigas is only obtainable in Diamond, Pearl, Platinum +