Read the rest of Chapter 4 of Beginning Arduino Programming, starting with the section titled "While." "While" is the most important part of this reading, and you can skim the rest; I almost didn't assign it, but you will see those other code concepts (such as "switch" and others) appear later in the book. Then begin Chapter 5. You'll be happy to see that we've already talked about most of Chapter 5 in passing, so feel free to skim and focus on the parts that contain things you don't know. You can stop reading by the time you get to the extended "State changes" example. It's a nice example, though we're already doing lots of others in class.

As usual, find the reading forum and post a question or comment.