One thing you need to avoid is working with power tools, at least until you get more experience. A poorly-operated power tool can change your life, and not for the better. "How-hard could it be?" Think about going the rest of your life with only one eye, or minus several fingers, etc.
One of the best things you can do, is to be humble-enough to tell someone, "I don't know how to use a ____ (insert tool name here), safely." Unless you are working with a psychotic ******* (it happens) they should be able to help you to get the experience. Don't be miffed if someone tells you, "OK, I'll do it, watch." Don't expect a 10 minute explanation about how to use a sidewinder Skil saw, there's work to-do. Ask questions at breaks, but always be unafraid to inform a co-worker, "I don't know how to use/do that safely."
As a firefighter for 45 years, now retired, and a paramedic, I saw plenty of stupid behavior on jobsites, some unfortunate circumstances, and all painful. I have an X-ray I saved of a guy with a tapcon smack-dab between his eyes, it looked like a blue caste mark at-first, then I saw the phillips X. The x-ray lateral view of the cranium shows it's about 1-5/8" long, and its head is nearly flush with his forehead. He was conscious. He screwed-up.
Powered nailers are great labor-saving devices, but they can be dangerous, especially when carelessly-used. Never put your hand behind and in-line with something you're trying to nail with one of those. Even having your hand close-to where you're nailing can result in trauma, if you hit a knot.
Your local community college or trade school of the school district probably has some novice classes you could take to gain safe experience.
