Files you downloaded using this link should be put in Engine/Plugins not in your game project. Also, this zip does not include .dll files so you have to rebuild your project now.
The thing is, plugins are code based right now, so if you want to create your own plugin you will have to rebuild your project at some point. My plugin only helps you to get started by setting up basic plugin files structure. My plugin WONT rebuild your project for you so you have to do it manually.
Have you tried rebuilding your project?; ) Get your project solution (or engine solution), start it in Visual Studio and rebuild it, so the .dll’s get updated.
Cheers