Have you installed Storage Foundation/HA or just Cluster Server?
It is best to perform installation of both cluster nodes at the same time and then use the wizard to perform basic cluster config...
You may want to download the Installation Guides from here:
https://sort.symantec.com/documents/doc_details/sfha/6.0.1/Windows/ProductGuides/
Under Installation and Upgrade you will find:
Veritas Cluster Server Installation and Upgrade Guide - English
and
Veritas Storage Foundation and High Availability Solutions Installation and Upgrade Guide - English
These docs describe requirements as far as Private Network (heartbeats) are concerned and other pre-reqs.
Once basic cluster config is done, use this Guide to install SQL into the cluster and config the Service Group:
Veritas Storage Foundation and High Availability Solutions HA and Disaster Recovery Solutions Guide for Microsoft SQL Server 2008 and 2008 R2 - English