Right, it's just a technique that helps you see what you need to see when you use the CPT code book. It can be helpful on exams. Of course, learning how to use the CPT code book and becoming very familiar with it helps a lot more, but this technique can be useful.
Bubbling just mean that you circle groups of related codes. When you get to the CPT module, you will learn that some codes all begin with the same main part; and each has a different ending. You circle the whole group that begins with the same main part.
123456 These codes all begin with this text; the first code says this.
123457 ; The second code says this.
123458 ; The third code says this.
You are going to draw a pencil box around those three codes. Then, you are going to highlight the crucial bit of the main text and whatever part of the rest of it that distinguishes each code from the other.
It is pretty much a no-brainer, and it's really easy to do, but you should not do it during module two. In fact, I would wait until you have finished module three and are preparing for a CPC exam to do this. If you do it too soon, before you have had a chance to figure out exactly what is important to highlight, you will end up making a horrible mess out of your codebook. You also won't learn as much during the modules as you should. You don't want to rely on a crutch too soon. If you do you won't learn to walk on your own.
I have seen people do this in a non-judicious manner. What was supposed to be a helpful technique made their books impossible to use. If you highlight using the wrong kind of highlighters, it will bleed through to the back of the pages. If you highlight too much , it will be worse than not highlighting at all. If you are not careful when you draw those boxes around groups of codes, you will not draw them accurately and you will just make your book a confusing mess.