As for modifying the number of columns you will be limited to 1 or 2 with the layouts in CSS Form Builder.
I have custom forms to complete for my an insurance agency. They have a four column existing form. I followed the instructions in the form and "ONLY" on column displays. In other words it took and existing four column form and converted it to a one column form.
Two would be twice as good but very limiting and not very "flow-friendly."
How do I "at least" get two columns please. Thank you.