Cannot find the option to arrange product list in columns

hi

i want to change the product layout but i can not see the product list layout highlighted above. 

I would like to apologize for any inconvenience. It appears that the Product List Layout is only available to forms with the Upcoming theme.

I would suggest that before you make any changes to your form's theme you test it first on a cloned version of it.

You can change the theme of the cloned version of your form, select a Product List Layout, and then switch back to the original theme of your form after.

Here's the result:

Feel free to let us know if you need any further assistance.