Take a simple course or read a book. Internet has tons of shite on it.

But until you have the gun/stick/torch in your hand it means fcuk all. go guy a crap .99p car and weld on it with some scrap. Learn on THAT car. Weld up some exhaust that doesn't leak then you are ready to play.

I recommend mig and flux core to learn on. If you like it and want to move on to other people's projects or tinker some more buy a cheap chinese tig inverted and a bottle. that's my next step.