Multiple expanding/collapsing boxes - Automate?

Forgive my lack of experience, but I could not get boxes to expand with either of the two pieces of code you provided. Do I rename to match my settings. For example, where you have “Button” to I edit to “readMoreButton” or should your code work verbatim? I’m not sure I understand the first example vs. the second example either. Do I repeat this code five times to replicate the need of each box on my site? Again, please forgive my questioning. I appreciate your assistance and patience.