by I will be using Azure Kubernetes Service (AKS) to demonstrate the concepts, but by and large it is independent of the Kubernetes provider (e.g. feel free to use a local setup such as minikube).
To create the Kafka cluster: We covered most of these in part 1 - StatefulSet (and Pods), LoadBalancer Service, ConfigMap, Secret etc.
All you need to do is use the kafka-console-producer and kafka-console-consumer by pointing it to the client-ssl-auth.properties file you just created
I will not pretend to be a security or SCRAM expert, but do want to highlight that it is one of the supported and commonly used authentication mechanism in Kafka (in addition to other such as PLAIN)