How do I add Bootstrap theme to an existing Rails application?

Hi everyone! I'm new to RoR, I have followed the blog tutorial on the rails guide website and now want to add layout (Bootstrap to be specific) but don't know how to. I have read so many articles but still can't figure it out. Does anyone have some easy understand resources about this subject? Thank you

I struggled this for awhile as well. I figured it out with a free template from Creative-Tim and opened source the result. I also wrote up a blog post diving into the codebase here: https://www.dinosaas.com/articles/starter-app-1-argon.

The GoRails video here is also an awesome walkthrough - https://gorails.com/episodes/using-purchased-themes.