To create multi part forms, create a form, click on the button 'Add page'. In the right hand section 'Page options' select the following:
- Page title specifies the page's title
- Top text is the text that will be shown above the form
- Bottom text is the text shown below the form
- Page color sets the color for the page
- Page width (pixels) indicates the page's width in pixels
- "Previous" button is the name of the button that leads to the previous page (leave blank to have 'Previous' by default)
- "Next" button is the name of the button that leads to the next page (leave blank to have 'Next' by default)
Click 'Save' to save the changes.
To add fields to the page, click on the icon 
or the button 'Add field' (see Field Options for more info). Select the necessary field options and indicate the page where the field will be shown: in the field Page select the number of your page 1, 2, etc. depending on the number of pages you already added.