How do I learn advanced methods and tuning of queries for free by vertica official

You can learn pretty much anything you want to learn about Vertica for free on the Vertica Academy: https://academy.vertica.com/ If you just want to learn query tuning, there's a class on that specifically, or you can get a wider view of everything Vertica and get your Vertica Certification. It's all on-demand and free. If you want an instructor to come to your business (post COVID) or do a remote class, you can request that, but all the regular classes are free. I got my Vertica Essentials cert on there, and plan to re-up it to the latest version as soon as I get a chance.