Yellow Hertz Shuttle Vans

We are renting a car after our cruise and will use the Hertz shuttle to take us to the rental office. My question is - where is it located and will it be easy to find? We will be getting off the Allure, so we will be at Terminal 18 I believe. They said they run every 20-25 min so if the van is not there, is there a sign that is noticable to see to stand and wait? I was told we don't need to book the shuttle by Hertz, is that correct?

Thanks! Cathy