Where the arrow is pointing to in the below picture is what you click on to open the Layer Palette.

So if you have a project that has several layers, you will see the layers here. 
If you hover your mouse over a layer, a mini picture will pop up showing what is on that layer, like the above picture depicts.

When you want to work on a particular layer, you just highlight it in the layer palette.

You can name each layer what you want to make it easier to know what's on the layer.
You just highlight the layer and right click on it and choose the rename option.
After you rename it, just click enter on your keyboard.

~Summer °Ü°