Controlling LEGO Mindstorms Motor With Arduino Uno

I am a beginner programmer, and have just started using the Arduino. I have the Bricktronics Shield (https://www.wayneandlayne.com/projects/bricktronics-shield/), but I don't want to use the library they have for it. I found some information on the web, but I could not make sense of it. Does anyone have any experience with this?