Hi gogo415, welcome to the Linux Mint forums
Thanks for joining the forums! As for learning about all the Linux complexity, perhaps focus on two or three topics you want to start learning about and expand from there. The KDE UserBase Wiki
may be helpful to learn more about KDE, with a good introduction to KDE, a jargon file and a set of tutorials. If you want to learn about the command line, an excellent starting tutorial is here: http://en.flossmanuals.net/command-line/index/
Be sure also to check out the Community
website (tutorials, hardware and software reviews, ideas). You can also chat in real-time with other Linux Mint users. In the KDE Menu, in the Internet section, start the application Quassel IRC. After a short setup of your account you will be connected to #linuxmint-chat for general chat and #linuxmint-help for support with other Linux Mint users.
Have fun with Linux Mint