Not able Change Y axis Unit from seconds

I am quite new to Grafana, prometheus and GCP.

I have deployed the Kubernetes and prometheus, grafana from Click in Deploy option of GCP.

Default data source is prometheus.

I have also integrated Stackdriver as a data source for Grafana.

My goal is to get the instance down and up graph for all the instance of the same Project.

I am not able to change the y axis unit from seconds, it get’s reset automatically.