The normal way to upload to your server is to use your web hosting cPanel. Select the file option and use that to upload the script to a location on the server. The best thing to do is create a folder within your domain named something like ‘mySiteMailSys’. Upload the script directly into that folder.
If you publish your Sparkle site to disk and then upload via an FTP client, you could create the folder and add the file directly into the publish folder on your disk. This will then get uploaded when you next FTP your site.
You’re now all set to start creating your forms in Sparkle.