Lets take a look at the basic concepts. The following is a example of a simple hard-edged mask. The mask above was created by opening a new image, and then floodfilling with a solid fill a selection which I created. You can invert masks. Because Paint Shop Pro can apply this mask to a layer, you can have elements on other layers which will show through the masked areas.
Lets take a look at some examples.
The background layer is filled with a color. This is what will be in the background. It could be another image or be a series of layers containing elements. For this example I just used a solid color. Layer 1 contains the image of the bull.