This article links to information and procedures for adding and configuring a NAS as archive storage.
Archiving to network storage, including NAS, is supported for Unitrends Recovery-Series and UEB appliances that have been licensed for advanced archiving. Review the Limitations of archiving to network storage prior to adding NAS archive storage
Setting up NAS (NFS/CIFS) for use with Unitrends RecoveryOS (UEB or Recovery-Series)
refer to the following section of the admin guide.