Here is an HD Video Tutorial for you to view. Please note that before watching, you must know the Layer Mask Tutorial to understand use of Layer Masks.
NOTES ON VIDEO
– The key to hit on a PC to merge the top layer into the bottom layer is the ALT key. Hold that while left clicking in between the two layers. (On a Mac it’s the OPTION key.)
– Remember that unlike the video, you can carefully cut out the glass around the white borders to make it look like the image below. This is all done on the layer mask.
– Please ignore the messy job. It’s done a lot better on my Guilty Crown Wallpaper.