That's a universal hashboard tester or diagnostic tool to scan faults on the hashboard not only antminer hashboard are supported other well-known units are supported, including whatsminer.
That one is expensive. It's worth buying if you have a big mining farm. If you have only Antminer units, you can buy only an Antminer test fixture that supports almost all Antminer units and is much cheaper.
But since you already bought it and looking for manual then check this one
https://www.zeusbtc.com/articles/information/4218-picobt-universal-miner-tester-user-manualThank you! I appreciate your nonchalant attitude and willingness to help others solve their problems, regardless of the cause. Sorry, I don't have any points to give you; otherwise, I would have rewarded you for your help. Thank you so much!🌹🌹🌹🌹