how do i create a new image layer or hw do i add an image to a open file?
Are you using Photoshop CS5 or are you using the Photoshop Express editor on Photoshop.com? If it's the later, Photoshop.com's Express editor doesn't support layers. You would need to use and application like Photoshop Elements or Photoshop CS5. You can download a free trial version of those products here: http://www.adobe.com/downloads/