Although you've already received some good advice here, I'd venture to guess that the vast majority of us who shoot were taught be a friend or family member who's been shooting for awhile. I started when I was 5 shooting cans in a river with my dad.

You should be able to find a "10 Commandments of Gun Safety" or something similar online without any trouble. Take those principals to heart, then grab a shooter and ask them to take you plinking. Go out and shoot some cans. That's about the best way to learn the mechanics of a gun, figure out which stances work best, how to align your sight picture, etc.

If you're thinking of purchasing a gun, you'll want a .22 rifle. Cheap ammo, no recoil, quiet (relatively) report. You can get a single shot, bolt action, lever action or semi-auto. Though the single shot, bolt and lever action rifles will be more accurate and force you to take your time, a semi-auto offers the added capability of a marginal home defense weapon. I'd recommend the Ruger 10/22. It's an affordable, reliable standard first rifle and can be endlessly customized if you should ever need or want to.