Orucis Building in Maya- NOW I NEED HELP! (cough, Simon, cough)

So I believe this is the last building I'll be making for my city. Now I have the bridges to make, which is one of the things I need help. I also need to colour the buildings and I am unsure about the background for the final piece. Does it need to be a Photoshop background? And if so does it have to be our concept art or can I create a new background in Photoshop?