It connects your computer to a wifi connection via USB. You have to be near a router to pick up internet with it. It's not like a 3g or 4g adapter that uses cell phone towers and charges a monthly rate.
My living room computer is wired to an AT&T router. If I plug this adapter into an USB port in the back of my computer, will I then have wireless internet available?
If you have a router sending wifi, this will recieve internet from it and send to the computer you have it plugged to. It will have a software disk included in the package complete with instructions.