Layers are a very important aspect of GIMP. By drawing parts of your image on separate layers, you can change, move, or delete those parts without damaging the rest of the image.
To understand how layers work, imagine an image created from a stack of transparent sheets. Different parts of the image are drawn on different sheets. The stack can be arranged and sorted. Individual layers or groups of layers can shift position, moving sections of the image to other locations. New sheets can be added and others can be removed or made invisible.
Use the Layers dialog to view the available layers of an image. The text tool automatically creates special text layers when used. The active layer is selected. The buttons at the bottom of the dialog offer several functions. More are available in the menu opened when a layer is right-clicked in the dialog. The two icon spaces before the image name are used for toggling image visibility (eye icon when visible) and for linking layers. Linked layers are marked with the chain icon and moved as a group.