There are two links in the YouTube video that will let you download the program that I made to control the relay. I think you actually have to go to the YouTube website to see the links. Download it and run it after you wire the relay as shown in the video. Let me know if you need help.
This USB Relay did not come with a controlling app so I wrote my own, I used vb.net. Here is a link to the same exact one I purchased, the seller is from china but reliable. It will take about 2 weeks for delivery...
I’m glad I could help. There are many applications for this project. My next project will be with a wireless relay but it will be a while before I can start testing. Let me know how it goes.
I just recently wanted to do the same so I started testing with various devices and was finally able to come up with a simple & relatively cheap solution. I made a simple "How to" video on YouTube.