Blueimp gallery? Uh?

I have downloaded blueimp gallery. Now what? It says in the instructions install with NPM? What on earth do I do? There are lots of files, none of which tell me this is how to install. I have locked horns with GitHub before and just left with no assistance forthcoming. It is as if everyone else knows how to do something but will not share what they know?
Please help I have been trying for a number of years. I really have.