Steps:
- Subscribe to Watch the "testing" category of the forums ( http://forums.urbackup.org ) to get notified of activity there by mail.
- Get the most recent development version from here: https://sourceforge.net/projects/urbackup/files/ (look at the last updated date)
- Add your test system to the test matrix: Testing matrix
- If possible enable "End-to-end verification of all file backups" in the advanced settings. File backups will self-verify then. Also possible: Verifying file-backups with winmerge or KDiff3.
- Do a lot of backups and restores and report any usablity issues and bugs to the issue tracker: http://urbackup.atlassian.net/secure/