I understand. Social media is a big pond and it can all seem very scary at first. The first thing you have to get over if you want authorial fame is being afraid of other people knowing about your private life. If you are a writer and you get the sort of recognition that you are probably hungering for, people will want to know and the best possible way to invite them into your world is through social media.
I know that there's a lot of scary propaganda out there about social media ruining people's lives. Ignore that. Get over that fear. Just remember everything you say on social media is as public as yelling it in the middle of the street. Don't assume any part of the Internet is a purely safe space. If you're a writer social media can help you. You want to yell things in the middle of the street. That's the whole point.
The main ways I use my Facebook, Twitter, Google Plus, ello, and Tumblr is that every time I publish another poem or essay on the internet, the link gets cross-promoted on all of my avenues. I put videos of my performance art on my YouTube channel (along with cute dog videos, of course). And use Pinterest for things like nail art, tarot spreads, and promoting my visual art.
Twitter is the most powerful tool in a writer's social media arsenal. I once got the executive editor of Harper Collins to request samples of my latest novel, DIARY OF A HOLLYWOOD HEDGEWITCH, because he liked my Twitter and ongoing tweeting about writing the novel. Twitter can get you amazing connections, It can also get you noticed by powerful people. It can also get you embarrassed, so if you drink, don't tweet drunk. I don't drink any more, yay for that. Twitter is a very powerful tool. The way I first got into Twitter was just by logging every time I was doing something interesting. After a while I began to think in 140 word quips and it was on. It helps every time you publish something to promote it on Twitter, that always gets a few clicks.
Hope this helps.