Using Categories are one of the ways that you can organize your notes in Note Canvas. Think of it like the equivalent of a chapter in a book.
Categories are multi-level, meaning you can add a category inside of another category.
Aside from other categories, canvasses can also be placed here. The most recently visited canvasses appear at the top of each category.
As far as display is concerned, you can toggle a category's setting to show its subcategories, and this option will be remembered when you refresh the page.
To add a new category, click the blue "Plus" button at the top left corner.
To edit a category's settings, click the blue "Cog" button at the right side of any category to open the "Category properties" modal.