There is no real uploading like in the sense of uploading to a server.
What you actually do is to put the files and folders you're willing to share in your shared folder and then when other users are looking for these files, they will start to download them from your computer via the shared folder.
But that requires you not being firewalled (i.e. having no brick wall in front of the small globe in the bottom left corner of the LW window).
