Getting Started
Modonomicon uses both resources (translation files) and data (page definitions). If you want to live-reload your changes run /modonomicon reload to reload both resource- and datapacks.
This of course requires the changed files to be in the correct data/resource pack locations for minecraft to load.
The easiest way to get started is to follow the step by step guide Step by Step with Datagen. This guide uses datagen, a minecraft development feature, so it assumes that you know how to set up a mod project in either forge, neoforge or fabric.
Even for modpack creators it is recommended to follow this process. Datagen is a much more convenient way to create books and ensure they do not have errors that might keep them from loading or from working in game.
Manually creating books
It is not recommended to manually create books. It is much more convenient and error-free to use datagen.
If you instead want to manually create a book by editign JSON files directly there is currently no guide, however you can look at the generated results of the demo book here.
Further, you can reference the Structure section to learn about the file structures.