As per Nicolai's excellent post - start with the manual.
It is extremely important to understand which part of the process is the NBU admin's responsibility and which part the Oracle dba's.
NBU provides the plugin with the NBU client binaries. The backup admin helps the Oracle dba with the linking process of NBU plugin with Oracle.
NBU provides sample scripts - Oracle dba can use them as template or create own.
NBU provides log files (need to manually created - info in manual) to assist with troubleshooting.
Backup admin needs to create backup policy and ensure backup media exists.
Backup admin and dba need to ensure forward and reverse hostname lookup between Oracle client and master and media server(s).
This is a joint effort between you and the dba. The actual backup process is 100% done by the Oracle rman process. The plugin simply sends the data to NBU media.
This means troubleshooting is also a joint effort.
Don't attempt agent backups without co-operation from dba!
