Installing SuperSU -- I found a binary problem
There are many questions here, so the actual problem is somewhat unclear. Getting root app from Playstore (on an unrooted device) will not work. Therefore, I suspect it all relates to problematic/corrupt SuperSU zip - without it, you can't get root functionality. It is not recommended to tamper with SuperSU zip file! 

I suggest re-download SuperSU here and install it from recovery. If you can't install it, there could be other problems related to unsuccessful previous steps. Follow the rest of the steps from your guide and also seek help where the guide was originally posted. Good luck.