If you have not installed a plug-in in Lightroom, here are some notes to help. These notes are for Windows.
First you need somewhere to store the plug-in. Create a folder under Documents named LRPlugins (or something similar).
Next unzip the plug-in so the LRHazeFilters.lrplugin folder is created in LRPlugins, and the files Info.lua, LRHaze.lua, LRFilters.lua and LRHazeFiltersInfo.lua are in the LRHazeFilters.lrplugin folder. The location can be changed but you must have a folder named LRHazeFilters.lrplugin containing the four .lua files.
Now open Lightroom, click on the File menu and select Plug-in Manager… – the “Lightroom Plug-in Manager” window should open. Click the Add button at the lower left and navigate to the LRPlugins folder, select the LRHazeFilters.lrplugin folder and click the Select Folder button.
The plug-in should be installed and added to the list of installed plug-ins on the left of the Plug-in Manager window. The main part of the Plug-in Manager window shows details of the selected plug-in and should show “Status: This plug-in is enabled.”