Hopefully, you have a backup of the RAID data, which would allow you to restore critical files quickly. If you don't have a backup here are some tips to help:
Test a rebuild when the RAID is functional to ensure you have it properly configured and the management software installed.
Review the RAID documentation and learn how to handle drive failures and rebuilds when you first install the system. If you read the documentation after a failure, you might be too stressed, which can lead to mistakes that can make the data unrecoverable.
If you don't have a clear understanding of how the device crashed or the hardware failed, call Ontrack for professional help.