You can either buy an algo (biggest market is https://www.mql5.com/en/market) to use with MT4/5, or you can write one yourself. However, the way you have asked the question, I doubt you'll be able to do that.
Do they work? You'd have to ask the vendors for proof. Normally this is done with a myfxbook.com account. These are updated by the broker and cannot be faked.
EAs/robots comes up with the functionality to follow the technicals so they might requires monitoring during the highly volatile markets in my opinion and it is hard to reconfigure them if you aren't any developer.