So here you will understand in simple words:
A Target Group in AWS is basically a group of resources, such as EC2 instances or IP addresses, that can receive and handle requests from a Load Balancer to individual registered targets. Each target group has its protocol and port for routing traffic to the targets.
You can set up multiple target groups to manage different types of requests—for example, one group could handle general requests, while other groups handle requests for specific microservices
Elastic Load Balancing (ELB) provides three types of load balancers to manage traffic:
NLB: Routes Layer 4 traffic for quick, high-performance connections.
ALB: Routes Layer 7 traffic for applications that require routing based on the request’s content.
GLB: Balances traffic across regions, directing it to the nearest or least busy one for high availability.