What ancient sources from 1400 b.c. through 1000 b.c. either tell of, or depict the way POWs were shackled when caught and marched back to camp or confined after arriving? Pretty sure we don’t have anything specific for Moses, but we can make inferences from the surviving information from the surrounding culture. Fundamentalist Christians will blindly assume the Midianite POW’s in Numbers 31 merely reluctantly did as the Hebrews said and freely walked back to the Hebrew camp, but it seems reasonable to assume shackling was also normative back then.