How do I make the submit button on my form redirect to my download page?

How do I make the submit button on my form redirect my audience to a downladable file after filling the form?

Also, is there any way you can help that users only have to fill form once and then they can download any file on my blog anytime, anyday. So, they wont have to always fill form whenever they wanna download something from my blog.

Here's a guide: http://www.jotform.com/help/38-How-to-Redirect-to-a-Page-After-Form-Submission

For returning users, it's either you send the download page through email via form's autoresponder. Or you can create a show/hide condition in your form that if they click returning customer, it will show the download page URL.

If you need further assistance, let us know.