Writing documentation for a CMS is not an easy task, but you can help by suggesting items to add to the Documentation Forums.
Are there any files in the core Hotaru package that you'd love to understand, but can't get your head around? Are you trying to make a plugin, but are struggling with certain features? Are you trying make or tweak a theme, but need something explaining?
Leave a post below so we can document the stuff that you really need.