If you like this, you’ll probably also like https://seilevel.com/business-analyst-resources/rml-book/ and various videos and webinars from Seilevel on YouTube which I added to a playlist (not in any particular order so please scroll through it): https://www.youtube.com/playlist?list=PL2miG2CzrxakbZswQH-O4...

Also relevant, the Design Structure Matrix (DSM): https://dsmweb.org/ and https://mitpress.mit.edu/books/design-structure-matrix-metho... (mostly learning by example, not all software-relevant, available as an e-Textbook on Amazon) If you code in Java, IntelliJ has this diagram included.

Finally if you’re looking on advice on how to break software into modules based on making your API surfaces easier to use for yourself and other programmers, have a look at A Philosophy of Software Design. It’s not comprehensive, but it’s concise and relatively easy to read: https://books.google.ca/books/about/A_Philosophy_of_Software...