RobH_en_tn/2ch/26/15.md

he built machines that were designed by skillful men

Here "he built machines" represents Uzziah commanding his workers to build them. Alternate translation: "his workers built machines that were designed by skillful men" (See: rc://en/ta/man/translate/figs-metonymy)

the battlements

These were the corners of the city walls where soldiers could fight from.

he was greatly helped

This can be stated in active form. Alternate translation: "God greatly helped him" (See: rc://en/ta/man/translate/figs-activepassive)