At EC2 Dashboard, click on Load Balancers from the left-hand menu and then click on Create Load Balancer.
In the interface of choosing a load balancer type, select Application Load Balancer and click on Create.
In the ALB creation screen:
app-tier-internal-lb
In the Network mapping section:
In the Security groups section, select Internal-LB-SG. In the Listeners and routing section, select AppTierTargetGroup for the default action. Scroll down to the bottom and click on Create load balancer.
Complete the load balancer creation for the app tier.