1. Learn basic C and C++ programming, which is always a good starting point for other higher and lower level programming languages

2. Learn about data structures and memory handling (pointers) https://www.geeksforgeeks.org/data-structures/

3. Try to understand how an OS works (e.g. linux) https://github.com/tuhdo/os01

4. Buy an Arduino or alternative with some I/O. https://www.arduino.cc/