In order to show a list of all artifacts in your project, we need to either force you to use a cumbersome web upload system; or scan your project area for new artifacts.
We have decided on the latter; regularly scanning your project area for new downloadable artifacts.
If you've uploaded a bunch of artifacts, or have an indeterminate number of changes in your site, you can trigger a full scan of your repository. New artifacts will be assigned to the Unknown Version, and any missing artifacts will be detected.
You can also use the Remote API to register an artifact immediately.
You will also want to review the process for Classification of Artifacts.