install bootstrap vue
npm install vue bootstrap bootstrap-vue
//then in main file
import { BootstrapVue, IconsPlugin } from 'bootstrap-vue'
// Import Bootstrap an BootstrapVue CSS files (order is important)
import 'bootstrap/dist/css/bootstrap.css'
import 'bootstrap-vue/dist/bootstrap-vue.css'
// Make BootstrapVue available throughout your project
Vue.use(BootstrapVue)
// Optionally install the BootstrapVue icon components plugin
Vue.use(IconsPlugin)