For each instance you wish to setup you need to create a separate Resource Group within the cluster resource manager.
As each instance needs its own resource group you’ll need a static IP address, unique hostname and LUN for each resource group (at least 1 LUN). (Yes each instance needs its own unique hostname on the network.) After you have created a resource group and created the storage resource for the LUN within it, as decided on the hostname and IP Address you’ll be using you can get started.
Run through the installer just like installing the default instance on the cluster. Instead of selecting the default instance, enter the instance name. Give it the unique IP Address and hostname of the instance. Then run through the rest of the install wizard. It will install on the other nodes just like installing the default instance.
After installing your instances will look something like this.
CLUST1 (The Default Instance)