Kali and penetration testing in general is not a "basic" discipline. If you are not aware of the protocols, and how they interact with eachother, or how data flows, you can't expect to dive right into the "practical" side of pentesting and Kali use. You maybe should start with something like Ubuntu and complete
http://www.linuxfromscratch.org/. You should have a relatively solid linux foundation if you complete that and it is "practical" as you said. As for the networking side of things and protocols etc, they can be dry but they are necessary to learn. You have to walk before you can run.