Download the bash script with wget https://github.com/mildmelon/betterlockscreen-ubuntu-installer/blob/master/betterlockscreen.sh
You may need to make the script executable chmod +x betterlockscreen.sh (may need to be run as root)
Run the script using source betterlockscreen.sh
Or feel free to clone this repo, make changes as needed, and submit a pull request for any environment specific needs.