is col-6 is abootstrap class name code example
Example 1: bootstrap grid 2 rows
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css" rel="stylesheet"/>
<div class="row">
<div class="col-md-4">
<div class="well">1
<br/>
<br/>
<br/>
<br/>
<br/>
</div>
</div>
<div class="col-md-8">
<div class="row">
<div class="col-md-6">
<div class="well">2</div>
</div>
<div class="col-md-6">
<div class="well">3</div>
</div>
</div>
<div class="row">
<div class="col-md-6">
<div class="well">4</div>
</div>
<div class="col-md-6">
<div class="well">5</div>
</div>
</div>
</div>
</div>
<div class="row">
<div class="col-md-4">
<div class="well">6</div>
</div>
<div class="col-md-4">
<div class="well">7</div>
</div>
<div class="col-md-4">
<div class="well">8</div>
</div>
</div>
Example 2: col-md-6 bootstrap
<div class="col-lg-2 col-md-4 col-sm-3 "> Your Stuffs </div>
/*
col-lg for large
col-md for med
col-sm for small
enjoy :)
*/