Too Long; Didn't Read
Every div, image, and paragraph, etc.. are all boxes. Each of these boxes has the same attributes that can be altered to change how they are displayed. These attributes are margin, border, padding, and lastly your content. The most helpful resource to help you learn are the development tools that are built into every major browser, such as Chrome, Google Chrome, that can help you understand what is going on when you're developing a web site. At the bottom of the page, you can change one of the box model attributes you just learned about!