How do I install a relay receiver?
The "how to" is you send that rubbish back to the dark place.  It is not safe nor legal, and doesn't even fit our wiring.  You bought it in a way that circumvented the systems that assure quality, safe products in the consumer retail stream.  Don't do that with electrical gear. 

Then you buy any of a wide variety of products which do that same function, work with standard radio interfaces, but much more importantly, standard plugs and sockets so you can hook them up without creating an unsafe condition.  And most importantly of all, these products follow our safety standards and have a proper UL or ETL listing (third party testing proving it). 

Those include smart bulbs, smart bulb sockets which piggyback onto an Edison base, smart outlet modules that plug into a standard socket and give you a controlled socket, etc.  There's no shortage of these products.  Your local big-box stores has pages and pages of them on their website.