Bootstrap is simply a package of CSS, JavaScript, and font files. You must be confused why we used the term installing with Bootstrap here. Well, there are two different ways of using Bootstrap in Rails. The first one is to directly copy the Bootstrap files at proper places in the Rails project. The second one is the Bootstrap Sass way. It is because of the second way that we used the term installing. It also comes as a gemset that can be bundle installed in any Rails project. We will explore both the ways in detail in this section.

There's also a third way, using Bootstrap files from CDN, which is the simplest of all. We will explore this at the end.