I don't know how to use a comptuer

This image is the result of my lack of knowlege of Photoshop. I do not know how to use the program at all. I googled my first and last name, and blended two of the pictures i found, one of Marilyn Monroe, and one of an old lady. I only knew how to use the eraser tool on Photoshop, so I used that to fade the old woman's face and layer it over Marilyn Monroe's. I also used the eraser tool to erase out the background of the picture of the old woman. To me, Photoshop is very stressful, and I am not confident at all in my abilities to use the program.