Every single episode. One right after another. After watching these, you'll be super smart, guaranteed. (Note, we don't guarantee this action will make you smarter. We just wrote that to make the description more impressive. We're. Sorry. [Not, that is not an entirely sincere apology. Though, we didn't want to deceive you, dear watcher.]).
Schematics are the language used to describe circuits to other people. The first and second part show individual symbols for common components while the 3rd part uses the Arduino Uno schematic to show what common circuits within a schematic look like.
Understanding Electronics can be tough. These videos are introductions to many of the concepts around Electronics. They can help to improve the answers you get in forums or make Google searches more productive.