The following is my suggested layout for this Class. Your main php script should be located at ROOT level (i.e., first level). Your subordinate scripts are located in the includes directory. Your images are located in the images directory and your css files are located in the css directory.
Considering this Class will explore numerous examples, your example scripts should be located within your examples directory. Of course, those example scripts may use scripts and other files that are common to all examples. That fact will require you to figure out how to reference them. Those paths will be addressed in class.