Using Obsidian
Core functionality
The basics
The file browser graph view Using obsidian to learn about obsidian the command palette
Syncing and Backing up your vault! — several methods
Going Automatic
tags templates periodic notes tasks dataview
outside of obsidian
Fleeting notes app TimeTags for youtube - browser extension or Media extender for obsidian Matter - webclipper/reader Raindrop.io - bookmarks (free)/ webclipper(clipper is premium)
There are many other integrations - if you can think of a way of consuming or annotating content, there is probably a way to automatically sync it into obsidian.