Hi @marco-b
You should be able to achieve that using this code:
<?php if( have_rows('blocks') ):?>
<div class="row">
<?php while ( have_rows('blocks') ) : the_row();?>
<?php if( get_row_layout() == 'full_screen' ):?>
<?php elseif( get_row_layout() == 'box' ):?>
<div class="col-sm-3">
<!--content-->
</div>
<?php endif;?>
<?php endwhile;
</div>
else :
I hope this helps.