All plugins are installed the same way:
- Download the zip file.
- Unzip the plugin, and move the resulting jb_xLR.lrplugin folder (on Windows) or file (on Mac) to wherever you’d like to store your plugins. My preference is to put them in a folder on Dropbox, and to avoid putting them in folders under the Mac’s Library
- Bring up Lightroom’s Plugin Manager and tell Lightroom about that folder via the Add button.