www.digitalocean.com/community/questions/how-do-i-open-ports-on-an-ubuntu-server
www.cyberciti.biz/faq/ufw-allow-incoming-ssh-connections-from-a-specific-ip-address-subnet-on-ubuntu-debian/
Initial Server Setup with Ubuntu 20.04
www.digitalocean.com/community/tutorials/initial-server-setup-with-ubuntu-20-04
Install PostgreSQL on Ubuntu 20.04
www.digitalocean.com/community/tutorials/how-to-install-postgresql-on-ubuntu-20-04-quickstart
Find files via CLI
vitux.com/how-to-find-files-on-the-ubuntu-command-line