They're all bad. The official docs are the only place to go. Half of the time other resources are out of date or just plain wrong.

Start here: https://kubernetes.io/docs/tutorials/ Look at all the diagrams in the tutorials but don't bother with the interactive stuff.

Then learn the more detailed concepts here: https://kubernetes.io/docs/concepts/

Once you understand the lingo and the general idea of what the different functions are supposed to do, just copy some example deployments and try to get something of your own working.