"Hello I am working in Preset Manager in CSS Form Builder - Form Groups."
so to launch the CSS Form builder wizard, you are using the edit button from the preset manager?
Instead of launching form builder form the preset manager, you should be launching it from the web assist menu.
Open a page in your site that you wish to add the form to, the go to Webassist -> Forms -> Insert New Form.
Next to the form selection, you can click the edit button to edit the the form contents, after editing the groups or the contents, you will the option to save them as new presets.