This is a covering for the body made of metal links or chains.
# he built machines that were designed by skillful men
Here "he built machines" represents Uzziah commanding his workers to build them. AT: "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.