How can you narrow your topic to a single spoke or to a sub-header of a spoke on the map?

The information that you find on the following sites may be of help to you. I hope that it is.

single spoke and sub header spoke - UsingEnglish.com ESL Forum (http://www.usingenglish.com/forum/ask-teacher/24175-single-spoke-sub-header-spoke.html)

https://www.askmehelpdesk.com/advice/t-47074.html