When looking at books or other lectures, it was very difficult to learn initially because there was no distinction of what was important. This lecture selects and teaches only the most important core concepts, and it really feels like I'm getting a grasp of it, just as the lecture title suggests. Reading through the materials you provided thoroughly, solving the fill-in-the-blank problems, and following along with the practice exercises takes less than an hour, but the learning efficiency is really good. I think I can establish this core foundation and then snowball from there.