PBS Pro 14 is effectively the same thing as PBS Pro 13, but geared for the open source community. You may find the documentation for PBS Pro 13 (including the installation guide) here: http://www.pbsworks.com/SupportGT.aspx?d=PBS-Professional,-Documentation
Because the open source release does not contain packages such as PostgreSQL, it requires them externally. Depending on the OS you are running, there may be differences in versions of these components. Obviously, we can't test every combination so please proceed with caution. It is possible that upgrading an existing installation could corrupt the PBS Pro database, so I encourage you to backup anything you might need if things don't go as expected.
I would recommend that you generate RPMs so you can easily install the PBS Pro components on multiple systems. There are instructions for generating the RPMs here: https://pbspro.atlassian.net/wiki/display/PBSPro/Building+PBS+Pro+Using+rpmbuild
Once the RPMs are installed, you may need to update /etc/pbs.conf and PBS_HOME/mom_priv/config prior to starting the PBS Pro services. If the services fail to start you should see instructions on what needs to be updated.
If anything goes wrong, please let us know so we can get it fixed.