in installation guide it is clear..
to simplify this..
first allocate the storage disk to the nodes where you want to place the catalog and config database
i.e after allocation.. format it and mount it
then create a new group under cluster window and add this disk resource under that group
then copy the software on node 1
when you run the install select the cluster install
further the installation select the disk you added
i have installed this many times for a POC, which included on doing on 32 bit, 64 bit 2003 box and 2008 box
understand the guide properly and start the installtion
at any point you get struck, message me
even symantec has a very good resource in support who looks after cluster calls.