Within Oracle Enterprise Manager you can give everyone the option to look at all the parts of the stack however based upon a certain role people do want to have focus on their part of the stack. This means that a standard dashboard is not very usable, some people will want to focus on the entire stack for a specific department or customer. Some want to focus on the database and others want to focus on hardware.
Oracle Enterprise Manager provides you with a couple of standard dashboards which do provide a point from which you can start. Selecting a dashboard that is close to your role is the first step, after that you can customize your dashboard to show exactly what you want.
The below video shows how you can customize your dashboard. In this video you get a quick first impression to help you getting started.