Download latest OpenCDS runtime war file from the Releases page.
Rename the file to opencds-decision-support-service.war
(this step is not absolutely necessary, but will make your runtime match other instructions in our documentation, and so it is probably a good idea unless you know what you are doing).
Stop Tomcat
Copy the opencds-decision-support-service.war file into the $CATALINA_HOME/webapps (Linux/MacOS) or %CATALINA_HOME%\webapps (Windows) folder