A good habit to get into is to name your layers for easier identification in larger complex images. Ok, we add the text and forgot about the sign again. Not to worry the text is locked into the layer and can be easily moved now. You can now add the sign on it s own layer without disturbing the rest of the image. Your image is now saved thanks to using Layers.
Layers are also good for applying effects to one part of an image.
A layer with brush effects and lighting is a good example of this technique. They can also be used to make transparent parts of an image. To achieve this you would move the transparency selector on the layer to a lower Opacity. Stay tuned for the advanced tutorials. FoX1 has Left the Game.