The word "set" is a metonym for choosing, and the words "over themselves" is a metonym for "to rule them." AT: "chose a king to rule over them" (See: [[rc://en/ta/man/translate/figs-rpronouns]])
# It was night when he rose up ... surrounded him and his chariot commanders
It may be helpful to reorder this sentence and to add implicit information. AT: "The Edomites surrounded him and his chariot commanders, but Jehoram and his army fought against them and escaped during the night" (See: [[rc://en/ta/man/translate/figs-explicit]])
# to this present day
This refers to the time when the book of 2 Chronicles was written. See how you translated this in [2 Chronicles 5:9](../05/09.md).