The importing features for LUA scripting is currently under construction. At the moment you must manually add scripts yourself.
To add scripts manually you will have to go through the same process as Quick Start, and paste the .lua script code into the file, and the same for the .json if any data is required with it. Remember to save it!
Watch the video below for a guide on how to do it.
Make sure the script is set to "Run as" option is set correctly as determined by the script creator.
Below is a tutorial video created by community member: ToaRex to help others with installing custom scripts. Thanks @ToaRex!