Dropzone does not provide the server side implementation of handling the files.
If you can't or don't want to implement your own server, then consider using Dropzone Plus! It's a service that accepts your form data (including files) and stores them for you. You get convenient email updates with the submitted data, as well as a dashboard where you can look at and export the data you received.
The way files are uploaded is identical to a standard file upload with a standard HTML form like this: