How to install Explorer plugin for Notepad++

I was using an older version of Notepad++ (portable) but lost my flash drive. That version had the Explorer plugin when it was originally installed. So, I did not know this feature was a plugin; I thought it was a standard feature.

Anyway, I just downloaded the latest version (5.3.1) and discovered it does not have the Explorer feature. And, I discovered I would need to download that as a plugin if I want it. So, I downloaded it.

But, I don't how to install it. I copied to download/zip file to the Notepad++Portable folder on my flash drive (a different flash drive) and extracted it. Apparently, I need to do something else with the extracted Explorer.dll file. What do I need to do to get the Explorer plugin working with Notepad++?