Eventually I would like to have samples of my source book to show you, my loyal readers, but right now I'm organizing, so instead, I will share my process of thinking.
Right now I'm working on a smaller outline, that I will expand to a larger outline. I broke it up into chapters of what I would like share, (which may be more as I go through all my information, but you have to start somewhere).
So my suggestion for you, and this can even apply to your novel, as well, is start with an outline. It can be as basic or complex as you like. I'm sure your English teacher probably said the same thing when writing essays for their classes. 😁 For me, I like to start with the simple and then get super complex so you are basically writing the book/essay as you go, with the need for a good transitions here and there when you are done with the outline.
I started with chapter headings. So far I've got the following:
1) A small introduction. Most books of this nature give a quick overview of what to expect. It's good not only to get the reader an idea of where you are going, but to show case what you want to share.
2) Races. A world is filled with people and most people who read about your world want to know about those people. Here you can fill in those things which may have not hit the pages of your novel.
3) History. Sure, you give a small glimpse of your world in your novel, but I bet, like me, you have tons of history you made up to make sure things flow in the time line, (and to use as novel fodder maybe later). Show case all you want, but don't bog down in uninteresting events. We don't want to know farmer Joe planted seeds 40 years in a row, but we do want to know the world was saved in said year by said people.
4) Area descriptions. This is where you can make your world shine. Show case those large areas of your world, and those small spots you want to share with the rest of the world. It becomes a travel log for you reader. If any of you played 2nd Edition D&D there were travel guides for the Forgotten Realms called Volo's Guides, which had everything from haunted locations to inns to stay at. I probably won't get that in-depth, but it is something to think on, and is certainly enjoyable.
5) Gods. My world, and many fictional worlds, rely on their God/Gods as major player in their stories. Mine is no exception. In fact, my Gods/Goddesses become characters, mostly my God of Magic, but many others as well. Here you can talk about their ethos and their followers, along with symbols, colors, attire and hated enemies!
6) Life in General. What do people do for a living? What are their holidays? What money do they use for exchange. Reading a book, you pick up some of this, but not always a lot of it. Here, you could expand as much, or as little as you like.
7) Major groups. With these you could bring up major players in the world. My major bad guys are the Wizards of Shaniko. My major good guys are the Knights of Tridon. And there are all sorts in between.
So, keep on writing! You will get there, as well!