When you create a reference in the load balancer to a stand-alone server or cluster, the server or cluster is added to the list of target servers and clusters the load balancer controls. The referenced server or cluster still needs to be enabled before requests to it are load balanced. If you created the load balancer configuration with a target, that target is already added as a reference.
To create a reference using the Admin Console, on the left frame, click the HTTP Load Balancers node and then click the desired load balancer listed under the node. Open the Targets tab, click Manage Targets and in the Manage Targets page, select the required target. Alternatively, you can create a reference using create-http-lb-ref. You must supply the load balancer configuration name and the target server instance or cluster.
For more information, see the documentation for create-http-lb-ref and delete-http-lb-ref.