Wrap a series of buttons with .btn in .btn-group.

Combine sets of button groups into button toolbars for more complex components. Use utility classes as needed to space out groups, buttons, and more.

Place a .btn-group within another .btn-group when you want dropdown menus mixed with a series of buttons.

Make a set of buttons appear vertically stacked rather than horizontally

Instead of applying button sizing classes to every button in a group, just add .btn-group-{sm|lg} to each .btn-group, including each one when nesting multiple groups.

Create split button dropdowns with virtually the same markup as single button dropdowns, but with the addition of .dropdown-toggle-split for proper spacing around the dropdown caret.