I've spent the last couple of hours working on applying a bootstrap theme to my website. I don't have any experience with css, so I had to study up on that. Which lead me to research SASS. The cool thing about Hugo is it has a toCSS method to convert sass to css for you on the fly.
The documentation for bootstrap is not bad, but I don't have any real experience using it. I watched the following youtube clip to help me out.
So far I haven't needed to theme anything yet, so my sass file is looking bare.