The following is by no means exhaustive, but is a good place to start your hacking journey. Kali is only a platform, its a very capable penetration testing distribution IF you learn how to properly use it!

Learn your way around Unix based systems, and that includes BSD, Linux and Mac OSX they all share a lot underneath;

Learning Perl regular expressions will help you in your hacking journey;

Get to know the MITRE framework and how vulnerabilities are being exploited;

Some of this site can be a couple of years old, but in general, the way of doing things hasn't really changed, so it's a good beginner starting point to get to know some of Kali's tools;

OSCP also have a great metsploit resource;

We have Portswigger who gave us the excellant Burpsuite tool;

Don't forget that hacking is about more than just computers;

If you want to learn programming, or scripting, or even get some free cyber security lessons, check out free code camp;

Perhaps you like to study malware, and want to get into reverse engineering;

For practicing what we have learned we have great sites like..

Hack The Box;

and Try Hack Me;

Hope this short list is of use to some, happy Ethical Hacking!