Networking - Connecting Extra Routers

As I have already explained, I'm a novice when it comes to home networking. being a two story house, we are more than likely going to need more than on WIFI router. So that I can get make this happen I thought that it might be a good idea to do some research on how to do so.

The image below explains what I want to happen, the article link and video explains (to my satisfaction) how to make it happen. There is more to it than just plugging in cables... unfortunately!