Just kinda learn how the FAA number system works. Most of the time, it makes sense.
61.87 student pilot flight requirements
61.107 private pilot flight requirements
etc.
61.85, 61.105, etc knowledge requirements.
61.93 kinda breaks that up for the student solo xc requirements
Once you learn the numbering stuff, just gotta know what decimal part are the 80 series, 100 series, 180 series, etc.