So sorry for the inconvenience, mate!
That thing you are getting with the huge list of folders is actually something I have encountered myself on a number of occasions and caused a lot of head scratching to be sure. That was super common for the longest time then it just stopped. You are officially the second person I know of in the last couple of years that this has happened to... and you won't BELIEVE what the problem is.... Are you ready for this? Unzip the file with some other app. Tadaa.... THAT is actually the problem, believe it or not! :O
Once extracted you should have the .unitypackage file and that is that. Install that into your Unity project and inside your project you will find a VERY small zip file that you then install on your website. The file is called wuss_login.zip. Once that is installed and activated you are good to go.
Of all the things you could possibly expect to go wrong, which unzipping tool you use... I know that was the last thing on my mind back when this happened to me, but...that is all it will take to get rid of your headaches :O Who would have thunk it!? :O