The discussion revolves around customizing the hamburger menu to switch themes and apply predefined filters, particularly to enable features like the Kanban Board Theme Component, Favorites, Discourse Assign, Agenda, and Tickets. PackElend asks how to add a menu entry for a theme that activates these components. nexo suggests duplicating the current theme, adding the desired components to the new one, and using the Hamburger Theme Selector plugin. PackElend clarifies whether merging themes is necessary, and nexo confirms that components should be added only to the duplicated theme if only the new theme needs them. PackElend then asks about additional hamburger menu customization options, and Canapin explains that the Add Custom Section feature allows navigation bar customization, referencing the official documentation.
Continuing the discussion from Different themes per category?:
Hello,
Can I add an entry in the hamburger menu what switches to predefined filter and activates the Kanban Board Theme Component (or any other of the those lsited below)
In addition, is shall make visible
in the navigation bar.
Duplicate your current theme, enable/add those components to the new one, give it a name.
Next, install the Hamburger theme selector and them to both themes. Let me know how it goes 
means I merge the current one with the Kanban Board Theme Component?
If you only want the new theme to have Kanban boards, then add that component to the duplicated theme only.
slowly getting it thx 
are there options to customize the hamburger menu besides of addin the theme selector?
as far as I remember navigation bar can be customized but cannot find the how.to anymore.
The way to go is now the Add custom section feature which is available in any up-to-date Discourse install.
See more at Custom sidebar sections being tested on meta