to add a file field to your form go to Insert -> Forms -> File Filed
in the upload behavior select the file field, in the upload path, enter the path to the folder you would like the file to be uploaded to.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.