Grids work just like they do in Bootstrap, based on a 12 column grid. Make a row and give it columns. By default the grid holds it’s structure on every device.

<div class="row">
  <div class="col-3">.col-3</div>
  <div class="col-4">.col-4</div>
  <div class="col-5">.col-5</div>
</div>
.col-3
.col-4
.col-5

Responsive

You can use the responsive lg modifier to make the grid snap back to vertical stacking on smaller devices.

<div class="row">
  <div class="col-lg-3">.col-3</div>
  <div class="col-lg-4">.col-4</div>
  <div class="col-lg-5">.col-5</div>
</div>
.col-3
.col-4
.col-5