Domain Cluster Config - Missing Dependency

I am trying to setup keycloak in domain cluster mode, but when I run the start up script I recieve an error message indicating I am missing a dependency:
Required services that are not installed: “jboss.jdbc-driver.postgresql”
Services with missing/unavailable dependencies: “jboss.jdbc-driver.postgresql”

My directory structure is keycloak/modules/system/layers/keycloak/org/postgresql/main

I have copied the jar file (postgresql-42.2.9.jar) in the main directory, as well as my module.xml file which look as follows:

<?xml version="1.0" ?>
    <resource-root path="postgresql-42.2.9.jar"/>
    <module name="javax.api"/>
    <module name="javax.transaction.api"/>
Have I copied the jar and xml file in the wrong location?

How did you go about setting up postgresql on your Keycloak server?
What were the steps you used, maybe I could help. I just finish connecting my Keycloak server to MariaDB, there were some trick in getting this done.

Not Declare JDBC Driver in

@ Ncollins246

Path Should be : …\keycloak-12.0.4\modules\system\layers\keycloak\com\postgresql\main

<?xml version="1.0" ?>