en_tn/jdg/09/43.md

divided them into three units

"separated them into 3 groups" (See: rc://en/ta/man/translate/translate-numbers)

they set an ambush in the fields

"they hid in the fields to attack the people by surprise"

he attacked

Here "he" refers to Abimelech who represents himself and all of his soldiers. Alternate translation: "they attacked" (See: rc://en/ta/man/translate/figs-synecdoche)