Login to Admin Console
Click on Servers tab on left hand side, New tab on right hand side
Enter name of your managed server, listen address, port, select "Yes, create a new cluster for this server" ( if you haven't created before and want to create ), click next
Enter Name of you cluster and click on finish.
Now Managed Server MS1 create and assigned to cluster Cluster1.
If you want to assign more server to the cluster -
Go to Servers -> select New tab on right hand side
Enter name of your managed server, listen address, port, Select "
Now select cluster on left hand side, click on name of cluster on right hand side
Enter cluster address as -
here it's - MS1:7003;MS2:7004