(1) Sheng: Sheng is the earliest musical instrument with a free spring in the world.
(2) Phoenix blowing: blowing sheng's voice.
(3) heavy doors: heavy doors.
(4) Thousand tree flowers: flowers on thousands of peach trees. Blowing sheng's voice came from the sky through the rosy clouds, and I don't know which one is outside the wall.
The doors are locked and there is nowhere to look, but I guess there must be thousands of peach blossoms in them.