No, it’s not just for criminals, tough they use it, too
No, you won’t be a hacker in 1 Month, asking things like: How to hack XY in Deep Web Forums, they will just laugh at you or tell you to learn to code…
Don’t just install the TOR Browser and surf right away on your main machine!
I’d suggest you instead to either use a Whonix Virtual Machine or a Tails Live USB. For most users, installing the Whonix Virtual Machine will do the trick.
If you go with Whonix, what you want is ~8GB RAM at least a Dualcore CPU with hyperthreating or ~4 Cores. Why do you need this much for Whonix? because you will run basicially 2 virtual Computers inside your real Computer. One Gateway and one workstation, which is configured to use the Connection of the Gateway. This way you can make sure, that if the Workstation is compromised, your Onion Router aka. Gateway isn’t.
If you go with Tails, you need to ask yourself a question: Do I want everything gone, when I shutdown the Computer or do I want a persistent Storage? both can have it’s advantage on it’s own. If you plan to chat or want to take part in a Conversation, I’d suggest you to go for the persistent Storage. simply that you find your site you were on or your chat partner(s) again.