en_tn/gen/22/11.md

the angel of Yahweh

Possible meanings are 1) Yahweh made himself look like an angel or 2) this was one of Yahweh's angels or 3) this was a special messenger from God (some scholars think it was Jesus). Since the phrase is not well understood, it is best to simply translate it as "the angel of Yahweh" using the normal word that you use for "angel." See the note about this phrase in Genesis 16:7.

from heaven

This refers to the place where God lives.

Here I am

"Yes, I am listening" or "Yes, what is it?" See how you translated this in Genesis 22:1.