I am Windows 10, Audacity 2.1.2, and can’t remember whether I installed from .zip or .exe installer.
I downloaded Anwidasoft DX Reverb Lite VST plug-in from their site at this url: http://www.anwida.com/download.asp
I moved the .dll file to the Audacity plug-ins folder.
I restarted Audacity. After the restart, the plug-in did not show up in Effects, so I found it in The Plug-ins manager and enabled it.
After restaring Audacity, the plug-in doesn’t show up in the list of Effects, nor in the plug-in manager. I have restarted several times, no luck. The .dll file is still definitely in the directory. (Program Files (x86)/Audacity/Plug-ins.