It is actually all written in the Snapshot Client Administrator’s Guide. You will really just have to read through it. I guess you could skip the parts that are not about your specific brand of SAN storage.
Offhost backup is relative easy to setup from Netbackup's side (Not many clicks really). It is the preparation that requires effort. You will typically have to work with your SAN storage vendor for copy-on-write or split-mirror type snapshot configurations, what they do and don't support, their best practices on doing this type of backup, their support policies, whether you are required to buy extra licenses for this SAN feature, what their host based VSS providers (or non-VSS providers on *nix) requirements are, whether some SAN software agents and CLI components will have to be installed on to which hosts (just the Hyper-V? Or the alt client too? Or the Nbu server too?), and what their OS compatibility lists are, where to store the copy-on-write blocks, when and how to sync/re-sync the splitted mirror, extra storage capacity requirements to your SAN, performance impact to the hosts and SAN for using snapshots, etc.
The actual "alternate client" is usually designated to be a Netbackup media server. This just means this is where the snapshot will be SAN mounted. The media server is a good place to mount it because you then just back it up to storage units directly attached to the same media server.
