Despite its name, Photography Editing has little, if anything, to do with editing. It's actually a photography guide that offers really specific tips on DSLR shooting. It's a fine user manual, but if you're expecting to edit your photos with it, you'll be sorely disappointed. It's loaded with helpful tips that will help you take better photos, though.
Photography Editing isn't really an app, either. It's just a scanned manual on how to take great photos with a DSLR. In addition to tips on shot selection, it includes detailed explanations of all of your camera's settings -- like aperture, shutter speed, and more. It even helps you understand advanced concepts like dodge and burn, rule of thirds, and leading lines. It doesn't recommend any editing styles or even any programs or apps that you should use to edit your photos.
Photography Editing would benefit from a name change to cause less confusion on what it aims to accomplish, but it can really come in handy as a guide for amateur photographers.