This is the list that works. You just copy and paste each line into browser's url box.
Let's examine their first example: site:.edu "forums register". This means that the Google will display only websites with .edu domains that contain a word forums register. That means that we're targeting forums, where we can register, to get back links, and we only want domains, that end with .edu.
So this is a huge list of all the footprints that I'm using, and stop saying that getting .edu link is hard.