##Describe only the information about the public API that readers need to know
You don't have to go into detail about how every part of the public API is implemented - just a rough overview of the different classes and methods, and their uses.
For example, if you have a method that looks like this:
public UsefulInformation getInformation() {
// 100 lines of code
}
It's fine to not include the // 100 lines of code, and just include the method signature and a brief comment describing the method:
// returns a UsefulInformation object containing the current game state
public UsefulInformation getInformation();
If anyone wants full implementation details, they can look at the full source code that you have hosted in a public location (like a public GitHub repository), via the link you include in the challenge body.