Step by Step Composite image

 First i had to find the pictures of everything i wanted to add. I first got the picture of the computer and the computer background and dragged both of the pictures into photoshop. I then had to drag the computer background picture onto the computer and added a mask layer using the square with the circle in to do this. Then i add to press shift, cmd and i to make the picture disappear so i could then go over the parts i wanted using the paint brush tool. I had to adjust the size of the brush until i got the picture the way i wanted it. Next i had to add the next picture i wanted and placed it wear i wanted and added the mask layer. I made the picture reappear where i wanted it then i did this with all the only photos until i got the final picture.