A Grafana dashboard to visualize the metrics from the demo Golang application can be found here: https://grafana.com/dashboards/6671.
The prometheus.yaml contains a prometheus-operator/prometheus-operator Prometheus CustomResource object. It can be used together with the next file servicemonitor.yaml
The servicemonitor.yaml contains a prometheus-operator/prometheus-operator ServiceMonitor CustomResource. If you use it with an existing Prometheus, make sure the Prometheus is configured to pickup the ServiceMonitor in the namespace (serviceMonitorNamespaceSelector:) and the ServiceMonitor itself (serviceMonitorSelector:).
For more information on the Prometheus Custom Resource and prometheus-operator other CRs, checkout: