kubectl apply -k kustomize/postgres

This will create a Postgres cluster namedhippo in thepostgres-operator namespace.

To track on the progress of the cluster, you can run:

kubectl -n postgres-operator describe postgresclusters.postgres-operator.crunchydata.com hippo

This command is not shown in terminal due to the complexity of the response, but you can find more info about thekubectl describe command in the docs.