NEED ASSISTANCE TO UNDERSTAND HOW TO CREATE VS FOR 3 POOL

It depends - sometimes a service only supports a limited number of connections, and you can run multiple copies of the service on different ports on a single member. If each service is identical, then it does not matter which one services the request.

In this case, I suspect that the different ports are different services and the services need to be in different pools, with some irule/Policy logic to direct traffic to the correct pool.