Need assistance on End User Authentication Policy and Envoy Filter


I am new to Istio and I would like to learn how to apply authentication for Oracle Cloud. I have been following an article named Istio : End User Authentication by Ashish Singh. (It seems I cannot post any link here, so please Google that up instead). I already got a Kubernetes Cluster up and running with Istio and already got the appropriate response from Helidon running in Istio:

$ curl -X GET http://$EXTERNAL_IP/greet
{“message”:“Hello World!”}

Note: a few things in the article may not work as they are outdated or require updated solutions, but those are already taken care of. Do not pay attention to those. Instead, please see near the end of the article which is related to Istio Authentication, which points to these 2 yamls : istio-authn-policy.yaml and istio_envoy_jwks.yaml

However, as I am new to Istio and this article is from 2020, I got into this error when I applied these yamls:

$ kubectl apply -f istio-authn-policy.yaml
error: resource mapping not found for name: “jwt-example” namespace: “” from “istio-authn-policy.yaml”: no matches for kind “Policy” in version “

So I am not sure how to proceed further and I would like to request assistance. What would be the modern implementations of these yamls? Can somebody point me to the right direction?

Thank you