Create a new release. New release name is just the version number part, not the whole program name.
Upload the archive and signature.
Set changelog, release notes, etc.
Set the file formats. The format for the signature is Other.
Download archive and signature from file release system. Check signature matches:
$ gpg program-x.y.z.tgz.sig
Edit the program's web page (you can get to it from the software index page). Set the Current testing version to the new release's version number. The program will now automatically show up in the Testers wanted box on the news page.
Announcing the release
Add the release to the Zero Install (AddApp) feed (if any), marked as testing.
Click on the announce this release link at the bottom of the program's web page (it's next to the add new comment link) and enter a short paragraph about what changed. If you keep to plain text and write in the 3rd person, you can reuse this text for the freshmeat announcement later!
Do the Send Email Notification on the file releases page.
Send a release annoucement to the mailing lists (your new web announcement includes an automatically-generated message suitable for emailing to the list).