There is a .env.default file that adds root to the list of banned users. DO NOT REMOVE THIS UNLESS YOU KNOW WHAT YOU'RE DOING!
To run BeautyFile, you just need to add a watch directory and a port number like so:
node src/index.js /home/username/pictures 8080
Or you can use pm2 start myconfig.config.json. An example config is given in local.config.json