It only operates over the air if you have a local repeater with Echolink you can secure permission to use for the net.
There is a writeup here for using Echolink I believe. It's pretty simple. All you need is a device like a computer or smart device (phone, tablet, ect) and internet access. You can download the program for your computer on the Echolink website or the app from either Google Play or Apple store. Authorization is usually pretty quick and logging on is as simple as a click. Then you simply use standard amateur protocols to talk all over the world.