I like to start doing like this, but as you can see I'm like most people here don't have experience on electrical or electronic equipment

do you have an idea where I can start doing shit like this??? not up to professional of course but as a hobby where I don't need to electrocute myself would be nice

Building an e-bike battery from some random trash is a terrible idea. You won't electrocute yourself, but you are very likely to burn down your house when one of these cells randomly decides to ignite.

They’re already illegal in places, eg UK

There was a bit of discussion about that Frankenstein last year (it was a protest of sorts): https://news.ycombinator.com/item?id=42045621