How to plot on a grid

Posting a full source file (especially one that is over 4000 lines long) is probably not going to get you much help. The best way to get help is to ask for small chunks of help where you are running into issues. Try to generalize your problem so it is not very specific to your project. If you can do that, you will get a lot more help and then you can use what people post to get it working in your project.