Drupal 7 - Part 2: Create Sub Theme

In this tutorial we will learn create the Bootstrap sub theme for Bootstrap theme 3.1 and above. 

Theme to install:
https://www.drupal.org/project/bootstrap

Documentation:
http://drupal-bootstrap.org/api/bootstrap

The templates in the latest Bootstrap theme 3.x should be located here. You can copy over to your subtheme and override it.

html template: bootstrap/templates/system/html.tpl.php
page template: bootstrap/templates/system/page.tpl.php 
node template: bootstrap/templates/node/html.tpl.php
block template: bootstrap/templates/block/html.tpl.php

Relevant video on how to get the template files ready