Start with the High Availability guide:

http://support.veritas.com/docs/290237

You can install it as a clustered client or a SAN media server (it is called Enhanced Media Server in this guide).

The thing that took me a while to learn about clusters.

you have the physical server names and you have the cluster(virtual) server name.

backup any local drives C: and system state by the physical server name.

backup your resources by the virtual server name.  E: F:

this way if the E and F drives are on physical 1 or physical 2 you get to back them up OK.

if you backup E and F by physical name, and then they fail over to the second server, when you go to back them on on server 1 they are not there and you miss the backups.

So always backup your cluster resources by virtual name.

Other people may have some better tips beyond this, but that was the first thing I had to learn about clusters.

Install netbackup on the physical servers using that name.  and even though you are backing up by the virtual name it will still work.