There is a help Vault. I assume you’ve seen that already? That will teach you the basics of how Obsidian works. From there, the best thing to do is actually just create a test vault. Treat it like a temporary sandbox, and just play around! Try out all the features, and see how they feel to you.
As for Knowledge Management, this is an in depth topic, and I don’t believe there is one definitive or correct way to approach it. There is definitely no prescriptive way to approach taking notes. It depends completely on your own style and your goals.
- Read the threads in the Knowledge Management category on this forum. Sort by “Top” to see the most popular threads. https://forum.obsidian.md/c/knowledge-management/6/l/top
- If you want to go deep, you can’t match the quality of “How to Take Smart Notes” by Sönke Ahrens. This amazing book will explain the principles of powerful note taking, and explain Zettlekasten fully. But again, they are principles, not rules.
The suggestion “use tags not categories” is a bit like saying “use a plate, not a bowl”. It really depends on your own preferences, and whether or not you feel like soup tonight.
Can you say more about what you are taking notes for? Did you have any favourite note-taking apps in the past? What aspects did you like best? What brought you to Obsidian?