adding rows inside a col bootstrap code example

Example 1: how will it look when there is a container inside a a row bootstrap

  

    

      One of three columns
    
    

      One of three columns
    
    

      One of three columns
    
  

Example 2: a column inside another column bootstrap html

  

    Level 1: .col-sm-9
    

      

        Level 2: .col-8 .col-sm-6
      
      

        Level 2: .col-4 .col-sm-6