"Carry out" here is an idiom meaning to do something that was commanded or planned. Alternate translation: "to obey today's decree tomorrow also" or "to do tomorrow also what was decreed that they should do today" (See: [[rc://en/ta/man/translate/figs-idiom]])
This was a structure used for killing people by tying one end of a rope around the top of the structure and the other end of the rope around their necks and hanging them from it. See how you translated this in [Esther 2:23](../02/23.md). Alternate translation: "a frame for hanging people" (See: [[rc://en/ta/man/translate/translate-unknown]])