Advice: You will need to use lots of my code. The place to start is understanding that code. For this phase of the project you can interact with your fellow students as much as you'd like. Then, concentrate on one of the searches first. I'd reccomend breadth-first because it is less likely to result in an infinite loop. In case you do hit one, learn how to use "Force Quit" from the Apple menu. The Algorithm Design book does contain discussions of both types of search.
The buttons on the top of the window in the running version are to choose several modes. Clicking on "breadth" or "depth" should move Theseus one step towards the solution using the results of the appropriate method. Repeatedly clicking them will give you the full solution. "Animation" animates the process using breadth-first search. You can stop the animation by pressing "User". That way you could, for example, attempt to finish a partial solution.