The third step in the installation is to install the SitecoreUML Service for Sitecore, which is provided as a Sitecore package, on the Sitecore instance that you wish to generate the documentation for. As with the other components, the Sitecore instance can be installed on its own machine, the same machine as the SitecoreDXG components, or it can be otherwise hosted in the cloud.
To install the SitecoreUML Service for Sitecore, follow the installation and setup instructions in the SitecoreUML documentation. Note that you do not need to install StarUML or the SitecoreUML Extension for StarUML. You only need to install the SitecoreUML Service for Sitecore. Also note that SitecoreDXG supports version 1.3.6+ of SitecoreUML.
Important Security Note
The SitecoreUML Service for Sitecore is not meant to be a secure service and should only be installed on non-public, pre-production environments behind a firewall. In case you have the service installed on both your CM and public CD, note that the SitecoreUML.CM.config (the config that registers the SitecoreUML service route) must be deleted from the CD environment or else the endpoint would be open to the public. For more information, see the SitecoreUML documentation.