Assuming that you already setup the showcase resource group as described in Setup AKS Cluster, we are ready to setup a private container registry in that group.
You will need to setup an unique Azure name for the registry as alphanumeric characters with a length of (5-50). In my case, I am using: "sjefvanleeuwenshowcase"
We can create the registry using az cli.
az acr create --resource-group showcase --name sjefvanleeuwenshowcase --sku Basic
When visiting your resource group in the azure portal, you should see the created private container registry next to your AKS cluster.
This concludes setting up your private registry.