Installation
Installing Bootstrap is very simple. In the <head> section of your HTML page, add the following (before your custom style sheet declaration):
<link rel="stylesheet" type="text/css" href="css/bootstrap.min.css">
In the above example, the bootstrap.min.css file is being pulled in from a local /css directory.
A better solution (assuming you will always have Internet access while accessing the site) might be to use a link from the official CDN (content delivery network):
<link rel="stylesheet" type="text/css" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">