Oh, that doesn't matter. Now you can do it for the first time.
First click on 'Login or Register' in the middle of the page. On the page you get, it says 'Not registered? Register now for free!'. Click on that link. Type in your personal data and click then on the button 'Signup now'.
Then you are registered. Now return to the main page (where the link I gave you points to) and click again on 'Login or Register' (in case you aren't logged in after the registration). There you have to type in your username and password. Then click on the green check mark or press enter.
Et voilá, there you are in the uploading section. Click on 'upload file'. There type in some data and select the file you want to upload by clicking on 'browse...'. Then click 'Send File' and you get a page that the file has been uploaded. There you will also find a download link. Copy that link (by selecting it - right mouse click - copy) and paste it in a forum message so that we know it!
This must be clear enough I think! I'm looking forward to playing the levels!