There is no help page, no beginners guide, nothing. It took me a lot of trial and error to do anything at all and have no idea how to get it to handle bookmarks.
I searched the web for a beginners guide but found nothing.
If I ever find such a guide, I may give it another try.

An absolute must have. This is a game changer.

The single most important usability addon Ive ever encountered! I am quite stoked that Firefox will bring Treestyles to the native Browser.

I encountered some quirks with the Addon sometimes, like after closing hundreds of Tabs that the "x" button of a tab doesnt work any longer and you got to restart the browser,
or the quirk that if you restore a previous session due to accidently closing the window, that all the temporary container tabs are sitting ducks without the tmp-container wrapped around them - the tabs than need to be relaunched in a new created tab that hosts a tmp-container.
But despite that, I never lost any tab or anything!
Great addon - and my goto on every machine since ever!
With some usercss you can even get rid of the tab-bar, which is great to save vertical space and make use of wasted pixels for website content!

I still prefer Sideberry over the native Firefox "Vertical Tab" feature: It takes less space, allows for grouping, better shows grouped tabs, allows for colors, and actually has so many settings that you will be overwhelmed at first!

Many thanks!

The most essential and interacted with segment of my browsing experience.

Tab-Gruppen können nicht einfach gewechselt werden, somit ist es für mich nur eine Tab weitere Tab-Ansicht

it's sooooo simple but good

This is not first time that after closing and opening the browser, all tabs are lost. Very unstable add-on. Not suitable for work.

Ce n'est pas dans ma langue

Must have extension! So many options.