What is a block id in Squarespace and how to find one

Let’s say you found an awesome plugin that makes your summary blocks look amazing, like this one on Ghost Plugins. However, you only want it to apply to one summary blocks. How do you do that? In this tutorial, I’m going to explain what a “Block ID” is, how to find it, and how to use it to apply code to just one block in Squarespace.