Possible meanings are 1) "on the threshing floor that belonged to a man named Atad" or "in the threshing floor at a place called Atad" (See: [[rc://en/ta/man/translate/translate-names]])
The translator can add a footnote that says: "The name Abel Mizraim means "the mourning of Egypt.'" (See: [[rc://en/ta/man/translate/translate-names]])