how to make n x n grid with bootstrap code example

Example 1: no-gutter bootstrap 4

  
.col-12 .col-sm-6 .col-md-8
  
.col-6 .col-md-4

Example 2: ordering collumns in bootstrap

  

    

      First, but unordered
    
    

      Second, but last
    
    

      Third, but first