How to bring up the menu screen?

Hello there,

This is my first time ever using Apple TV. I believe I have plugged in all the cords correctly, and the Apple TV light is on, however when I turn on my TV it takes me straight to normal TV with channels and such. I have tried pressing the Apple TV remote menu button, and holding it down for 3 seconds, however nothing changes on my TV - no kind of Apple menu comes up. I have a Samsung TV with a Denon receiver.

If this helps, I have the power cord connected to a wall plug and the HMDI cord connected to a slot in the actual Samsung TV labeled "HDMI In 1 (DVD)".

My Mac that I plan to stream Apple TV off is a Macbook Air with OS X Yosmite (10.10.3)

I have a Netfilx Account.

If anyone has any kind of ideas or suggestions as to why I cannot seem to bring up the Apple TV Menu (which I need to connect to wifi and stream movies from my Mac), comments would be greatly appreciated.

Thank you very much!