https://docs.redhat.com/en/documentation/openshift_container_platform/4.18/html/monitoring/configuring-user-workload-monitoring#enabling-a-separate-alertmanager-instance-for-user-defined-alert-routing_preparing-to-configure-the-monitoring-stack-uwm

Enabling a separate Alertmanager instance for user-defined alert routing has # used for commands while only $ is required.

Change:

1. oc -n openshift-user-workload-monitoring get alertmanager/pods
   to:
   $ oc -n openshift-user-workload-monitoring get alertmanager/pods