If you noticed in the previous box, there are a set of 4 boxes (div tags) next to each other. Being able to arrange elements is important. HTML gives some very flexible ways to do it. But this flexibility can make it complicated. In general, HTML specifies the basic idea of how the different elements should be arranged, and the browser lays out the elements to best fit them on the screen according to some complicated rules.

You won't need to do too much of this for class, but get used to seeing HTML that does things to create desired layouts.