I learned off a site called SecurityOverride.org which had a bunch of hacking tutorials, combined with a few Linux virtual machines installed on my PC (thank goodness for fast gaming rigs!) that I hacked.

There are a number of ways to learn. As long as you don't go around hacking other people's stuff, you're good.

P.S also if you really want to learn, install TOR browser and search the dark web for hacking eBooks or other guides because they're everywhere there. A good way to delve in would be to go to the hidden wiki and find websites with the .onion domain.