Hi Ross.
After clicking Click here to submit a File you should be presented with 10 file selection boxes.
Please note, at the very top of that section there is a drop down alongside 'File is online?'
[attach=#]
This defaults to 'No' please change this to 'Yes' if you wish to have the file visible and downloadable.
There is an alternate method, using ftp, where you can upload hundreds or thousands of files, and then via the web control panel, import them into a single section
With both methods you will, I am afraid, need to edit the description for each file after upload (you should see a little 'Edit File' link under each file in the browser.
I'll put together a guide on uploading via ftp.