Guides

Below are links to some of the best guide I have found:

Learn the ways of Linux-fu, for free. https://linuxjourney.com/

Introduction to Computer Organization: ARM Assembly Language Using the Raspberry Pi: http://bob.cs.sonoma.edu/IntroCompOrg-RPi/intro-co-rpi.html

C++ Language: http://www.cplusplus.com/doc/tutorial/

MySQL Reference Manual: https://dev.mysql.com/doc/

The Apache HTTP server project: https://httpd.apache.org/docs/

Official PHP Documentation: http://dk2.php.net/docs.php

Raspberry PI: http://www.raspberry-projects.com/pi/