Steps to hold a single backup
1. Navigate to Recover > Backup Catalog
2. Expand the list of backups for a protected asset
3. Select the backup you wish to hold and click the Hold button above
CAUTION: backups held in this way will remain on hold forever until manually unheld. To unhold a backup you would use these same steps, but when you select a held backup the "Hold" button changes to "Unhold"
To see a list of backups which are currently held you can navigate to Reports > Retention > Legal Hold Backups