"Other users and shared" occupying too much space

I'm new to Mac and I have an update. Trouble is, I can't get it, because "other users and shared" occupies a gargantuan amount of space. Which is strange, as this is a brand new machine, which only I use and there is no shared content. I have added very little to it. So what on earth is this "other users and shared" business, and how do I find it and get rid of it?