en_tn/2ch/27/03.md

He built the upper gate ... he built much ... he built cities ... he built castles and towers

Since Jotham was king, he may have had his workers build these things. Alternate translation: "He had his workers build the upper gate ... he had his workers build many things ... he had his workers build cities ... he had his workers build castles and towers" (See: rc://en/ta/man/translate/figs-metonymy)

the hill of Ophel

This is a hill in Jerusalem. (See: rc://en/ta/man/translate/translate-names)