Hi @netmage Welcome to the forum!
The article shows a manual installation approach - which is not a bad approach, but passbolt has worked up some better solutions that are easier. First, the installation script approach has been reported to work with minor adjustments on the script.
More recently, passbolt developed a debian package (originally for Debian 10) which has also shown to work on Ubuntu 20.04. The intent is to eventually have an Ubuntu package. Future updates are made easier with a package like this.
The help site is in the process of getting updated and will eventually reflect this.
One note: the debian package installs into these directories:
… and not into
/var/www/passbolt as was standard previously.