It contains the K8's cluster and makes it easy to recreate things if (when) you screw up. You wont spend the majority of your time fixing the cluster instead of learning how to use the cluster itself.
Then you can pick any K8's tutorials or courses. As previous folk have said there are plenty of them about. Udemy, Coursera, Pluralsight, Oreilly all have really good resources. Or just use all of the free tutorials and resources out there. Search GitHub for some 'awesome lists' etc.
I can't give any detailed advice on courses having not done them myself! I have used books online and kind to figure stuff out though!
Good Luck! James
There are plenty of courses online that will help you learn K8S or K3S, some even for free. I tried the Udemy course on Kubernetes Certified Administrator (iirc).