Map of Computer Science:
Binary Numbers and Number Systems: Watch the tutorial below to understand the number systems and be able to make conversions between them. Having good understanding of Binary and Hexadecimal number systems will greatly help you understand programming languages and data representations.
Khan Academy: Binary Numbers
Supplementary Textbook: https://books.trinket.io/thinkjava/
Java Tutorials: https://codingbat.com/java
How to use Command line:
Windows: https://www.digitalcitizen.life/command-prompt-how-use-basic-commands
MAC: https://www.taniarascia.com/how-to-use-the-command-line-for-apple-macos-and-linux