Add Sections to Page

I’m wondering how to add sections or containers to pages on my twenty thirteen child theme, similar to this site’s layout: https://www.nitrografix.net/

This is for a portfolio site, and I would like to have different colored sections for the about, portfolio, social, contact, etc.

Is there a plugin for this? If I need to add sections or containers, do I do this in the index.php file, then tag each section in the page’s text editor?

Any guidance would be appreciated.