I did not fully read this guide, can’t comment how correct it might be.
In any case you should install either 1.7.9, or more preferably 1.8.2 CMS, in 1.8 series CMS case, we would suggest docker although manual/custom installation is also possible, but you will have to make few additional steps, which are automatically done for you while using docker.
Various installation instructions are here - http://xibo.org.uk/manual/en/install_cms.html (for docker and non-docker variants)
1.7 series will have less steps there, the documentRoot should be for example var/www while in 1.8 it must be var/www/web there is also no XMR, zeroMQ etc.
After installation (especially manual/custom one) please see Xibo CMS Post-Installation Setup Guide (for 1.8) or Xibo CMS Post-Installation Setup Guide - 1.7 Series (for 1.7)