Good to learn more in Kubernetes network policy for CKx exams and EKS. Below are resources:
1/ read official doc and try to understand them well - https://kubernetes.io/docs/concepts/services-networking/network-policies/
2/ bookmark samples for exams and EKS setups - https://kubernetes.io/docs/concepts/services-networking/network-policies/#networkpolicy-resource
3/ do more practices at https://github.com/ahmetb/kubernetes-network-policy-recipes
4/ visualize (image below) and try more at https://editor.cilium.io/ - it allows you to save the final netpol in k8s netpol OR Cilium netpol (EKS-A is using Cilium !)