How do I install and make use of heatmap.js?

I downloaded the most recent release from Github but none of it seems to work and to be perfectly honest, I’m not really sure what to do with it from here. I’ve never used a library before and can’t seem to implement it to even begin just playing around with it.

I’ve moved the folder to my project root and linked it in the HTML but nothing is showing for me.

Where do I even begin with things like this? I’ve tried to do lots of reading but I’m getting lost in a sea of various different libraries and package managers.

Thanks