That is Part 1 of Melody. There are 4 more parts on that topic, plus similar 5-part series on rhythm, harmony, and bass. When you have a little extra time, watch them all. It will take several hours. Or watch them one at a time and stretch it out over several weeks like an especially yummy box of chocolates. You will learn a lot. I did.
(If you have ever studied music in depth you may already know most of this, but the videos are still interesting. Watch them anyway.)
