Knowledge Base module will be released soon. It's available on the demo installation
You can test it in the Menu/KnowledgeBase
Remember to login as admin to see more features like access restriction.
Categories are main structure that allow you to create tree structure and manage access to Threads and notes (with all descendants)
Threads are something like shelves. Each category can have multiple threads. Every thread is a place to write notes.
Tree view is designed for easy structure overview and fast navigation.