Here "presence" stands for the people serving as witnesses. Alternate translation: "with the people of Heth watching as witnesses" (See: [[rc://en/ta/man/translate/figs-metonymy]])
Here "sons" stands for those who descended from Heth. See how you translated this in [Genesis 23:3](./03.md). Alternate translation: "the descendants of Heth" (See: [[rc://en/ta/man/translate/translate-names]])
This tells which sons of Heth saw Abraham buy the property. See how you translated this in [Genesis 23:10](./10.md). (See: [[rc://en/ta/man/translate/figs-distinguish]])