There is no such thing as a stupid question. I can't offer the same guarantee for my answer.
Chapters you read one after the other. Modules don't work that way.
If you have a large project it makes editing and debugging easier if you modularise your code.
For example:
The MENU module could store code for menus
The TOOLS module could store functions.
The MAIN module could be the main code page.
The code in the MAIN module calls procedures in MENU and TOOLS when needed.
You could of course place all your code within one module. It depends how far you are prepared to scroll down to find what you are looking for.