Now once you've found out your IP adress your going to use and entered it, i want you to enter the information you got before(from cmd) and put on that piece of paper. The last numbers can't be anything though it should be between 1-254 and definately shouldn't be the same as the routers IP address or this won't work. So if your routers IP is 192.168.1.1(Which it is by default) then you'll want something like 192.168.1.200.
Now your going to need to make your own IP address but it shouldn't be to hard seeing as it will be the exact same as your Routers IP address(Default Gateway) except for the last group of numbers.