in the css form builder wizard, click on "Customize CSS".
from the initial list, select "Form Elements", the select "Element Labels". Here you can set the Placement of labels to Top and the Alignment of the labels to Left.
for setting the width, you will need to select the "Form" option from the initial list and set the width for the form, then select "Form Elements" -> "Text" to set the width that will be used for the small medium and large text boxes.
select any other element types you will use in your form to set the widths for those as well.