How do I download a backup as a file?

Who can download

The admin console has no download screen. Downloads are in the end-user plugins:

cPanel: open Files → BackupWall in the user's cPanel (administrators can reach it from WHM, List Accounts, the cPanel icon next to the account).
DirectAdmin: sign in as the user, then Extra Features → BackupWall.
Plesk: there is no plugin, so no download screen yet.

In My backups, choose Download on a backup.
Choose Files, Files + Databases or Databases only.
The server builds the archive in the background, outside the account's home folder so a later backup never captures it. Open the Downloads page and wait until the status is Ready.
Choose Download.

An uncompressed .tar file. It never includes mail.
It carries no user or group IDs, so an archive extracted as root gives root:root.
It is kept for 48 hours, then removed.
On cPanel and DirectAdmin an interrupted download can normally be resumed, provided the web-server proxy at /backupwall-download is in place. On cPanel the installer sets it up for EA4 Apache only; on DirectAdmin a timer sets it up for the web server in use.
The link keeps working until its 6-hour token expires, the file's 48-hour limit passes, the download is deleted, an administrator uses "revoke all links", or the admin password changes. It does not end when the cPanel session ends.

The staging area is set in Settings → Server → Self-service downloads (Staging directory, outside any account home, default /opt/backupwall/downloads) with Download links. Make sure it has room: there is no free-space check, and a download that large needs that much space.
Large downloads are built with a bounded memory budget, so a 9 GB download does not run the server out of memory. PortWall has tested a 9 GB staged download.
For files without a panel or an account, use bw-extract. See Get your files out without BackupWall.