Understanding this code?

Since you seem to be asking a more general question, I will answer generally as well.

Learning to think like a programmer is typically what separates coders from programmers and programmers from software engineers. You see, coding is intrinsically not that difficult, it is just like learning a new language, so once you learn the syntax and keywords, then the ability to code things shouldn't be to hard.

What makes programming difficult is the process of actual ability to logically come up with an idea, break it into smaller parts, and then code those parts into a workable solution.

The only way to get better at this is to well...practice. Since you are a beginner, expecting to just be able to jump in an understand large amounts of code, or even coding a solution from scratch is unrealistic. However, as you get better you will eventually have the knowledge necessary to come up with complete solutions on your own, and you will naturally gain the ability to logically break down problems.

So in short, just keep doing what you are doing, it is only natural that you don't automatically get the hang of it. Just take your time, and do your best to understand the concepts that are being taught. Boring topics like: variables, functions, loops, and conditionals are the basic foundations of programming. So once you master and understand these topics, you will be well on your way to being able to code up applications from the ground up!