You need to be a good bit more specific with the questions if you want specific answers. Otherwise you get a general answer for a general question.
What Ardiuno shield? Well what do you need the shield to do?
Until you can answer that we can not make a suggestion.
You first need to build a single Bot and it sounds like you have never done this. So you have a good amount of reading and studying to do first.
Start by clicking on "Robot tutorials" in the upper right coner of this web page then read everything there. Then come back to these forums and read all the threads.