The order to work through the Kubernetes notes: concepts, local setup, daily kubectl, first deployment, config, networking, storage, operations and debugging.
Kubernetes core concepts: the mental model and core objects
Deploy one of your own services end to end on kind: Deployment with probes, Service, ConfigMap + Secret, Ingress, an HPA, then break it on purpose (bad image, failing probe, wrong selector) and fix it with the debug runbook.