They made the egg in two halves as thin as they could, like a real egg. They let it dry hard in the sun, and they were excited, because they had made a connection between birds (the egg) and mud, just as the story had hinted.
When it was dry, they sIowly put it in the fire- where it cracked and broke and nothing really happened.

But Orca and Ren kept trying every day until Ren had an idea: perhaps the eggs shattered because the spirit bird inside could not get out, so, they made a small hole in it for for the Spirit Firebird to escape. This time they pushed the smooth egg with its hole very sIowly into the fire, and heaped small and then large wood over it and when the wood was all burnt they covered it with grasses and earth to keep the Firebird still within.