As suggested, each datacard has an X,Y value that references their position within the form. Both start from Zero meaning 0,0 is the first card in the first row. 1,0 = second card first row. I take the trouble to provide an example because struggle ALWAYS when counting from Zero.
If you set your column count on the form to 12, it will try and 'fill' all 12 columns. You can manually set values of X and Y to create the layout you wish but if you put less than 12 datacards on a row, I advise you manually decide which column or columns will be >1 column in width which is completely possible.
Once you set all of the x,y coordinates to get the datacards in the right position, you can grab the edge and extend across more than 1 column if you wish.
The image below is only a two-column form but you can see the top three datacards are spread across both columns.
