Obsidian is a popular software for creating a second brain.

Fortunately, you can learn Obsidian from a beginner level to an expert level online for free by following these three YouTube channels:

1. Linking Your Thinking with Nick Milo

   When I first started studying Obsidian, I discovered this channel and have followed it ever since. Nick Milo, the owner of this channel, is a highly skilled Obsidian user and explains things in an easy-to-understand manner.
   
   This channel explains how to use Obsidian to create a second brain and expand your thinking and writing potential.
   

2. Zsolt's Visual Personal Knowledge Management

   This channel focuses on Excalidraw, a plugin used for drawing diagrams and maps in Obsidian. It also covers various principles of Personal Knowledge Management (PKM) and provides summaries of interesting books using Excalidraw.
   

3. Darin Suthapong

   Darin, the Thai YouTuber who owns this channel, created it to explain the famous Zettelkasten writing method.
   

   This channel also explains different ways to use and set up Obsidian in an easy-to-understand and practical manner.
   

If you dedicate time and seriously study these YouTube channels, you will become proficient in Obsidian before you know it.