The code for a Plex plugin is contained within a directory named with a “.bundle” suffix. As such they are often referred to as bundles. To install plug-in bundles manually, you will first need a link to the plug-in bundle. Sometimes the bundle will be posted on the Plex forum or available via link to download from GitHub. In order to install the plugin:

1. Download the linked file. If the link leads to a GitHub page rather than a direct download, select the “Download Zip” button on the page to download the zipped bundle
2. Usually, the plug-in bundle will be located within a zip archive. Unzip the archive as necessary.
3. Bundles downloaded from GitHub will usually have extra identifiers appended to the bundle’s filename, such as “-master”. Edit the bundle’s file or folder name to remove any text after “.bundle”
4. Copy or move the plug-in bundle into the Plug-Ins folder (see article linked below) on the computer running Plex Media Server
5. Restart Plex Media Server to make sure that the new plugin will be loaded.

Related Page: How do I find the Plug-Ins folder?