Describing given Java code & making a slight change - Urgent

Need in 24 hours (don't bid if you can't deliver in time) Essentially, you need to explain what each piece of code is doing in each class in more detail than the comments already provided. Need clear English for description & to be understandable by a novice. Can be done on on any text editor. Need a basic understanding of how to play Draughts(checkers) & Alpha-beta pruning. As for the slight change I need someone to change the loading of the 2 images as the pieces ("red" & "black" variables near the start of the checkerboard class) to draw two circle shapes & still work when run. Can be done anyway you like. Thanks