Before Bootstrap can work for us, we need to link to it.
In earlier lessons, we linked only to main.css. Now, in addition to main.css, we will link to a URL that hosts Bootstrap.
The HTML link element makes Bootstrap available to us. Remember that the link element is typically contained within HTML head tags.
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css"/>
href attribute is set to the URL
Let's explore what Bootstrap can do for us.