So I’ve finished the tutorial, and here are the final images. The first is without the sky and the other is with the sky (as you can clearly see). I have added some indoor lighting and from using my own expertise and knowledge, added the sky to my own accord. I am very happy with my model and I suggest you look up this guy at www.blenderguru.com if you are trying to get used to blender. You need to know basics for tutorial but otherwise, it’s great!
What I found out in this tutorial: Lighting and detail of the model makes ALL the difference to the finished render. The top of the building which was more detailed and had more textures looked much better than the bottom bit which was just a cube, modified. You need bounce lighting, so a lamp shining up and some other lamps just to light up the building a bit more and of course, one main light is needed (as the sun).