How do you install a microsoft xbox 360 adapter?

I got an adapter off of ebay for christmas and now i cant figure out how to install it i have a linksys wifi thing up stairs and my 360 is downstairs and whenever i plug it in a red light comes on I dont have any instructions for it and i need help desperetly because i dont want to waste around $100

go to the system settings then Connection or W/E and it should be in an area where it lets you choose a wireless connection in Range, if that doesent work, like mine didn;t the first time, you may have a faulty Wireless Adapter, mine was faulty but then i exchanged it for a new one.