Download the panorama you want and install it as you would with any other resource pack. You can have multiple installed, but you can only use one at a time, with the one you want to use being at the top of the resource pack order screen.
If you are using any other resource pack which changes the main menu panorama (Such as my other TeamExtreme Resource Pack), make sure to place this one on top of your other pack in the order screen, otherwise you will see no changes happen at all.
It is compatible with every Minecraft version 1.6 and later. Ignore any complaints about incompatibility from your game client. Even if your game whines about it, it is guaranteed to work.