Adding disks to cluster

Hello Team,

I got a request to add disk's to cluster, I have a cluster name "XYZ" and cluster nodes node1 and node2.

In the summary of the request , i have been asked to add 3 disk's to cluster XYX and that it must be accessible to both the nodes node1 and node2.

1)so , can i add disks to any one of the node(adding luns to physical server(node)) ? correct me if i am wrong..

2 )Also to my understanding cluster storage  is some thing like hard disk's connected to node1 and node 2(in case of 2 node cluster) if i am not wrong? or do we have separate storage(Luns) for cluster mapped to this nodes.?

Kindly make me understand on the above questions.

Thanks in advance!

Paramesh KA