Pro Tools only deals with plugins that come in its own unique plugin format - .AAX plugins.
Due to this, there will be a dedicated install location for Pro Tools plugins that can not be changed. This install location is as follows:
|AAX||/Library/Application Support/Avid/Audio/Plug-Ins||C:\Program Files\Common Files\Avid\Audio\Plug-Ins|
When you install dedicated plugin libraries in the app, they will automatically install the .AAX plugin files to the above install location.
Once in your DAW, these plugins should be readily available after installing through the plugin selector. The best way to load them is to create a new track, making sure that you set the track as a stereo Instrument track. Once created, you should be able to open the plugin.
More general information on library installation can be found in this article: Where is my library?