Different Bootstrap Css Files?

I downloaded a Web template which is based on bootstrap version 3. Inside the template I found CSS files named bootstrap-cerulean.css, bootstrap-journal.css, bootstrap-classis.css.

Solution 1:

All the bootstrap.css styles are most probably modified and integrated with those three mentioned custom css files that you got with the template so no, you don't need to link the default bootstrap.css anymore unless you're planning to override certain elements on the page to the default style (which I would recommend using a new css file with the few changes kept there for overriding the template's style rather than linking the whole bootstrap.css to the template.