This script helps install Apache Guacamole (tested on Ubuntu 18.04 LTS server) with an Nginx reverse proxy and Let's Encrypt SSL certificate.
Use the nginx-guac-install.sh first so that you can troubleshoot any issues related to the Let's Encrypt installation you might come across, which typically is firewall issues. I found this was where I had the most errors, particularly when you're setup includes going across a NAT/PAT firewall with port forwarding.
The guac-install.sh script will also install the latest Java JDK 8 which is the only major prerequisite required.
Much of this was taken from the following repos, but customized furher based on my personal preferences: