If this is the first script you're installing for the project, then perform these steps, unless otherwise stated on the script's page.

• Create a "Scripts" folder in the directory of your project

• In VX Ace, open the Script Editor and create a new script right before the last script that starts the SceneManager. In this blank script, paste the following for each new script you add:
  require "Scripts/scriptname.rb"
  Replace "scriptname" with the name of the script.

Download the .rb file from the provided download link into the "Scripts" folder for your project.

Add the require "Scripts/scriptname.rb" line in the Script Editor in VX Ace, replacing the "scriptname.rb" with the full name of the script file, with the .rb at the end.

Download the plugin from the provided download link to your project's "js/plugins" folder.

In RPG Maker MV, open the Plugin Manager, right click on an empty plugin slot and click "Edit"

Choose the plugin and tweak with the parameters as you wish.