If you're NOT interested in using a forms plugin, this 4-part series may be of interest you:

Have you ever found yourself needing to create a custom, multiple-​​​​page form in WordPress? I do… all the time! While you can use a variety of plugins to get the job done, they’re rarely perfect for your purposes. I’ve found that the…

via Design a Multi-Page Form in WordPress | DesignFestival.