Start by understanding what Tor and onion routing do in general, especially compared to a VPN. Read through this: support.torproject.org/about/ at the minimum. Also, understand that using these tools won’t keep you safe or anonymous if your intention is to log into any of your existing accounts. The goal should be to separate what you want to do anonymously and make sure to not have any overlap with whatever your existing accounts are since they’re already very much tied to you.

To actually use Tor I’d recommend starting with Tails OS: tails.net/about/index.en.html. If eventually you want to have a laptop or similar device that can persist some data maybe checkout Whonix: www.whonix.org. The best setup would honestly be Qubes OS, but it’s definitely not a good starting point for anyone not already familiar with unix-ish systems.