1- event_display Pod is showing errors:

{"level":"error","ts":1655723867.2054672,"logger":"fallback","caller":"http/transport.go:586","msg":"failed to get non-nil event from MessageToEvent","stacktrace":"knative.dev/eventing-contrib/vendor/github.com/cloudevents/sdk-go/pkg/cloudevents/transport/http.(*Transport).ServeHTTP\n\t/home/prow/go/src/knative.dev/eventing-contrib/vendor/github.com/cloudevents/sdk-go/pkg/cloudevents/transport/http/transport.go:586\nnet/http.(*ServeMux).ServeHTTP\n\t/usr/local/go/src/net/http/server.go:2387\nnet/http.serverHandler.ServeHTTP\n\t/usr/local/go/src/net/http/server.go:2802\nnet/http.(*conn).serve\n\t/usr/local/go/src/net/http/server.go:1890"}

 
2- Understand the KnativeEventing architecture and the associated components: 
Source, Broker, Trigger, Channel, Subscription

3- Understand the KnativeKafka component