en_tn_condensed/gen/23/18.md

to Abraham by purchase

These words complete the idea that begins with the word "passed" in verse 17. "became Abraham's possession when he purchased it" or "belonged to Abraham after he bought it"

in the presence of the sons of Heth

Here "presence" stands for the people serving as witnesses. Alternate translation: "with the people of Heth watching as witnesses" (See: rc://en/ta/man/jit/figs-metonymy)

the sons of Heth

Here "sons" stands for those who descended from Heth. See how you translated this in Genesis 23:3. Alternate translation: "the descendants of Heth" (See: rc://en/ta/man/jit/translate-names)

all those who had come into the gate of his city

This tells which sons of Heth saw Abraham buy the property. See how you translated this in Genesis 23:10. (See: rc://en/ta/man/jit/figs-distinguish)

gate of his city

The city gate was where the leaders of the city would meet to make important decisions.

his city

"the city where he lived." This phrase shows that Ephron belonged to that city. It does not mean that he owned it.