If you're planning to use Bootstrap on your Drupal 8 site, the first obvious thing to do is download and set up the Bootstrap theme. Then, during the site building process, there will come the point where you need to create a few layouts. These layouts could be used for content types with Display Suite, or for custom pages using Panels.

Implementing layouts using the Bootstrap grid system is simple thanks to the Bootstrap Layouts module.

Bootstrap Layouts is a module that ships a bunch of prebuilt layouts using the grid system in Bootstrap. Best of all, these layouts can be used between Display Suite and Panels, or any module which supports the Layout Discovery module

The layouts are configurable through Drupal's administrative UI. For example, you can adjust the width of a two column layout by choosing grid CSS classes from a multi-select field.