<div class="container">
<div class="row row-cols-md-1">
<div class="col">Column 1</div>
<div class="col">Column 2</div>
<div class="col">Column 3</div>
<div class="col">Column 4</div>
<div class="col">Column 5</div>
<div class="col">Column 6</div>
</div>
</div>
You don't need to remember all CSS classes. Just use the Bootstrap Editor instead.