Layers

In order to edit an image in Photoshop, it is necessary to create a series of layers. Every change made is created on a separate layer not sure about that.

You always start the process by creating a background copy, because the original background layer is locked so can't be edited. There are a few ways to create/delete a layer, for example you can right click on the layer and the options "Duplicate Layer"/"Delete" appear, or you can right click on "Layer" from the Selection Bar at the top of the screen and select from the drop-down menu.

Please note that when you select an image and paste it, a new layer with this pasted image is immediately created.