Prometheus alerts-manager

i have installed prometheus using helm charts in the k8s cluster , now i want to confugure alerts for the metrics the prometheus helmcharts consists of prometheus, node-exporter, alert-manager.
Now i need to create rules for the alerts . here i am unable to find the prometheus.yaml, i can able to see the only inside the pod which is also read-onlyfile ,
i am unable to edit the file the same for alertmanager.yaml also i am unable to edit.
how to fix this issue to get the alerts.

As you are deploying via Helm I’d generally expect the configuration to be managed by the Helm chart. So I’d suggest looking for a parameter in the charts you are using for alerting rules.

I can able to see the configuration in the helm chart but unable to see in the statefulset , when its deployed .
can you share which is the best method for it.