Hi.
Well, it's not very intuitive that one has to click on "Download" to upload a file.
Also, to a casual user "Download" and "Download Manager" do not look the same -- it's within reason that if they were the same thing they would also bear the same name, don't you think?
Therefore, the hyperlink in the "Upload Instructions" pointing to the exact place of the "Download Manager" would help.
I, for instance, would not have found it without either your assistance or devoting much more time to the investigative task of finding it (and we all are busy people, don't we?).
Anyway, amazing site this is, I have to say.
Regards.