Have you heard about the GRBL project yet? See the links below the Arduino CNC Shield V3 is GRBL ready.
Grbl is a free, open-source, high-performance software for controlling the motion of machines that move, that make things, or that make things move, and will run on a straight Arduino. If the maker movement was an industry, Grbl would be the industry standard.
This CNC shield is 100% compatible with this project and will get you going in record time.
The Grbl wiki page can be found here: https://github.com/gnea/grbl/wiki
The Grbl project page and software can be found here: https://github.com/gnea/grbl
And if you would like to do your own programming or use another sketch you can do that as well, Below is the pinouts as used on your Uno board.