daveyb91 0 Newbie Poster

Hello people,
A couple days ago I asked something for my assignment, which can be found here:
http://www.daniweb.com/software-development/csharp/threads/362561

Only.. I have to ask another question considering this.. I think I do understand the A* algorithm.. only I don't really know how to build the grid up for the cars.. I hope its not a very stupid question, but I'm quite stuck on this..
So, could anyone help me and tell me how I can build up a (car) grid for a Rush Hour game?

Thanks in advance..
Davey