How do I create a EtcdCluster in Kubernetes

Question

Etcd-operator (v0.5.1) examples have files with kind: "EtcdCluster".

apiVersion: "etcd.database.coreos.com/v1beta2"
kind: "EtcdCluster"
metadata:
  name: "example-etcd-cluster-with-backup"
spec:
  size: 3
  version: "3.1.8"
  backup:
    # short snapshot interval for testing, do not use this in production!
    backupIntervalInSecond: 30
    maxBackups: 5
    storageType: "PersistentVolume"
    pv:
      volumeSizeInMB: 512

source

How do I create such a kind, in Kubernetes?

The etcd-operator documentation doesn't seem to cover this, and they don't seem to have a dedicated mailing list (otherwise, I'd posted this question there).