The manuals are you best friends for this setup (hopefully the Symantec partner that sold you this solution is providing assistance):
You will need the following two manuals:
1.
Snapshot Client Admin Guide
This manual contains the requirements and policy attribute configuration for the hardware snapshot part of the backups. Important chapters:
Chapter 3: Policy configuration
Chapter 10: Configuration of snapshot methods for disk arrays
2.
NBU for SQL Admin Guide
This manual tells you how to configure policies with Snapshot Client option and also how to config policy in Cluster setup.
Chapter 7: Using NetBackup for SQL Server with clustering solutions
Chapter 8: Using NetBackup for SQL Server with Snapshot Client