The sun is indeed the honey of the Devas. The heaven is the cross-beam (from which) the sky (hangs as) a hive, and the bright vapours are the eggs of the bees.

In plain words: This begins a picture of the sun as honey enjoyed by the gods (Devas). Heaven is like a beam, the sky hangs from it like a beehive, and the shining mist is like the bees' eggs.