ofc i was referring to the the menu. Game included for clarity.
Daily game "live" analysis tool

Hm I only use the analyses from Lichess.org - never tried Chess.com since well... I don't like the website I know there are some great chess.com forums you could ask the question there

Right click on the move to ad evaluations etc. and to move variations up or down. If your opponents move is one of the moves you have analyzed your saved variations are automatic moved forward and can be the basis of your new analyzes.

You save variations just by making the moves and select save. And you can delete wrong moves or variations. It is a great tool.

I kinda get your description. But to nest a variation within a variation, it is stored in the same row? And distinguishabled only by a double parenthesis? (or triple if more than two?) I wish there was a manual

Yes! And you can move sidevariations up and down or promote one to main variation etc. And mark bad moves etc.
Some months ago the system broke down and was only partly and slowly restored. It may be because of that no manual exist.
One piece of advice: save often. So if you make a big mistake (like selecting delete 'all variations') or are having tecnical problems you can just go back to the game without savning.

I have another question if you know. How does "move variation up (or down)" work, and how should I use them?
I don't really understand my options here. And how to save variations, nest them (variations of variantions) and how (or if) i can connect them with opponents next actual move?