en_tn/1ki/05/14.md

in shifts

That is, there were three groups that took turns spending one month in Lebanon and two months at home.

One month they were in Lebanon and two months at home

Each of the three groups spent one month working in Lebanon and then two months at home in Israel.

the men who were subjected to forced labor

This can be translated in active form. AT: "the men whom Solomon was forcing to work for him" (See: rc://en/ta/man/translate/figs-activepassive)