Class Purpose
nav nav-tabs Navigation tabs
nav nav-pills Navigation pills
nav-stacked Vertically stacked navigation pills
nav-justified Justified pills or tabs. On screen size < 768px navigation pills are stacked
disabled Disables navigation tab or pill.
Dropdown menu can also be used with navigation tabs and pills

Creating navigation tabs using nav along with nav-tabs

Creating stacked Navigation pills use class nav-stacked

Nav tab with Justified use class nav-justified

Navigation Menu with dropdown