The “Kubernetes Up & Running” ebook (https://www.vmware.com/content/dam/digitalmarketing/vmware/en/pdf/docs/vmware-kubernetes-up-running-dive-into-the-future-of-infrastructure.pdf) is a good start for fundamentals. Then I’d pick up a hands on guide (e.g. https://www.amazon.com/dp/1800209673/) to get some experience.