how to create an html element that is not to the bootstrap gried code example

Example 1: row class in bootstrap

/*
In Bootstrap, the "row" class is used mainly to hold columns in it.
Bootstrap divides each row into a grid of 12 virtual columns. 
In the following example, the col-md-6 div will have the width of 6/12 of the "row"s div, meaning 50%. 
The col-md-4 will hold 33.3%, and the col-md-2 will hold the remaining 16.66%.
*/

<div class="row">
    <div class="col-md-6"></div>
    <div class="col-md-4"></div>
    <div class="col-md-2"></div>
</div>

Example 2: bootstrap container width

--------------------------------------------------------------------------------------
Bootstrap Container Width			 					| Size        | Class Prefix
--------------------------------------------------------------------------------------
Extra small devices Phones (less than 768px)  			| None (auto) | .col-xs-
Small devices Tablets (greater than equals 768px) 		| 750px       | .col-sm-
Medium devices Desktops (greater than equals 992px)     | 970px       | .col-md-
Large devices Desktops (greater than equals 1200px)     | 1170px      | .col-lg-