Here are some links to sites that might be handy to use as extra information while you're learning Graphics:
https://learnopengl.com/
The course textbook, but is also goes much further and in more depth than the course is able to, so it's worth using this if you want to press on and try things that we don't have time for
https://open.gl/
Another site for learning OpenGL from scratch. Covers the basics in a slightly different way than the course and learnopengl.com, so worth it if you're looking for another perspective
http://docs.gl/
OpenGL Documentation. This has a lot of specific detail and is also able to show documentation for different version of OpenGL. Especially good if you're looking for specific functions and parameters