Here are a few terms used in the program that might be new for you:
Layer is a template in the work area.
Active layer is the layer you are working with at the moment. An active layer is indicated by a frame and its name shown in the info line.
Model is an image of a face, any part of the body or a hand with nails.
Desktop is the space where the model and all the layers are located. In the work area, only a part of the desktop can be seen.
Work in progress is the current condition of the work area, including the model and all layers. Work can be saved at any time to the hard disk and then loaded again later to continue working with the same model.