What to do if you don't know how to live?

This is a serious question. You don't know how you fit in with people (difficulty socialising and even holding conversations sometimes), you feel isolated, you don't know how to fill your time and literally mainly stay in bed on the internet (how I spent the majority of first university year sadly), you don't know how to actually live and enjoy life. Something that others may take for granted. Where would you start? Where would you look for help and to whom? How would you start living your life which is worthwhile, not to live as an insignificant person? Say the exact things you would do in this situation ... I would be grateful for serious answers.

Well, first I'd talk to a psychiatrist - to help me find the root of the feelings.

Next (or maybe in conjunction with), I'd go join an activity of some sort: a yoga class, a spin class, Tae Kwon Do, a crafting group, a book club... something that interested me, but that I didn't necessarily have to know anyone to jump into and get started.

Some background: I was left alone since an early age at the house all day until evenings, so I did what I did. I had little guidance. Now I feel lost and irrelevant.

Talk with a professional, that will help.

And you need to actively make an effort. Go out and try different activities until you find something you enjoy. Join a class or volunteer group in an area you're interested in. You'll be exposed to new things and different people to get social experience and broaden you're own life.

At university there should be lots of free clubs/activities.

You could try a life coach. They help you explore questions like these, and help you find answers that fit you.