Basically, the cluster is now up-and-running. However, during the Verification & Synchronization step, it will complain about not having a non-IP network. The next part is for setting up a disk heartbeat network, that will allow the nodes of the HACMP cluster to exchange disk heartbeat packets over a SAN disk. We're assuming here, you're using EMC storage. The process on other types of SAN storage is more or less similar, except for some differences, e.g. SAN disks on EMC storage are called "hdiskpower" devices, and they're called "vpath" devices on IBM SAN storage.
First, look at the available SAN disk devices on your nodes, and select a small disk, that won't be used to store any data on, but only for the purpose of doing the disk heartbeat. It is a good habit, to request your SAN storage admin to zone a small LUN as a disk heartbeating device to both nodes of the HACMP cluster. Make a note of the PVID of this disk device, for example, if you choose to use device hdiskpower4:
# lspv | grep hdiskpower4 hdiskpower4 000a807f6b9cc8e5 None