"Socialist" in America right now basically means "liberal but angry" in the sense that our government has been taken over by extremest conservatives who do not believe that the law applies to them, but will happily kill and oppress millions of vulnerable people. What's socialist about Bernie is less his policies and more that he talks about class consciousness with people, which is necessary to stop a slide into fascism because god we are so far gone.

I am a democratic socialist because I believe in the democratic control of the means of production, that what our society produces and should not be controlled by a handful of psychopaths but a broad working class coalition. I feel that if we don't come together in this way our world is headed towards disaster. I believe in the Bernie campaign because I think the only way to achieve this is to give the working class a gradual taste of their own power, which I believe will stack on top of one another until we can make the steps we need to in order make a world habitable by all. This is all stuff that Marx talks about.

Democratic socialists generally distance themselves is from historical communist countries, though generally we acknowledge that the west has done some incredibly horrible things in the name of fighting communism. It's something to think RE: "it's never worked anywhere", it was never allowed to work because the most powerful nation in the world always stepped in to violently oppose it. A clear example of this is what happened in Chile in the 1970s, when a US backed coup overthrew a peaceful democratic socialist government in the name of free trade.

I hope this helps. I'm not a big reader into this kind of thing but I can answer any questions you have.