Mirror computer using AirPlay

You need a Mac running Mountain Lion (OS 10.8). Then, on the top bar near the clock, you will see an AirPlay icon.

I have a similar problem i have the newest operating system and a brand new apple tv and a brand new macbook i'm getting very frustrated

As SeaBeast said but you Mac needs to be mid 2011 for all models except MacBookPro which needs to be early 2011 or later.

Make sure you are on the same network, apple id and all home sharing is on. If that doesn't work reboot modem and Mac.

If you Mac is older or you run a PC try a third party app called airparrot.

jules