Sounds like you may not be ready to read this tutorial just yet. Maybe get more experience in the terminal, and read docs on specific languages (elixir has good ones, for instance) or take a hands-on course (like Codecademy Javascript, etc).

Then, once you have more experience, you can go back to that tutorial and try reading it with more polished eyes.

What you've posted is the equivalent of me taking a new interest in cooking but applying to culinary school. If I haven't cooked in a real (production, high volume) kitchen, it's all gonna be Greek, overwhelming, and turn me off.