I added both of the pictures i found on the internet first.
I then changed the scale layer of the picture of the dog by right-clicking on it using the mouse.
I added the layer mask of the dog and pressed the brush tool
Then I shaded the sides of the dog so that It will show that the dog is really standing there.
I also zoomed in the picture by pressing the zoom tool and left-clicking on the picture, so that it will have more details on it.
Then, I pressed the move tool so that I could drag the picture.
Then I took a screenshot of the picture by pressing command-shift-4 and put all the pictures here.