well firstly the groudon in steam cave is FAKE!
the real groudon is when you complete the game and complete the dungeon "shimmar desert" at the end of the dungeon you fight groudon, defeat him and with a bit of luck you can recruit him.
you can onley unlock shimmar desert after you found sizor and obtaind secret rank.
then go to spinda café and talk to the Pokemon at the entrance there are seven of these dungeons.
You evolve a psyduck.
The sky stairway
I don't think you can!
no, u can only recruit it.
Crystal Cave or Crystal Crossing
they ask you if they can be on the tam
It may take several attempts to recruit legendary Pokemon in Explorers of Sky.
Miracle Sea and Surrounding Sea
mission recruit or egg
you cant recruit him. there are only 492 Pokemon recruitible in the game
No, there isn't.
no but you will find the statue of arceus
sky stair ways all floors