It doesn't get any easier. Open box, connect as labelled, and viola! It works perfectly. Tough metal enclosure makes this product a winner. I will buy again.

returning them they dont work

These are very good at covering an HDMI signal to HDSDI 6g. But with a mac laptop (the only device I tried), when setting to a resolution of less than 4k (say 1080p or 72op) the output of the device remains at 4k/6g. This might be fine for some applications, but for my applications I need it to just mirror out exactly the flavor which is coming in to the HDMI input.

The good news... mono price has another device which does the trick. This one:
https://www.monoprice.com/product?p_id=21828

The other good news... it appears a return is easy at Monoprice too.