Click on Edit to change the settings of a Toplist:

First you need to select a Toplist Type: Choose from the three standard types or choose Custom Toplist to define your own Toplist parameters using the Custom Settings Button:

Depending on the Sensor type you have various parameters at your disposal that you can use to build your Toplist. After choosing your desired combination click OK to return to the Toplist dialog.
In the Toplist Settings group you can specify
· Interval: How long should data for a Toplist be gathered before a new Toplist is started
· Items: How many items do you want to see in your Toplist
· Number of Intervals: How many recent Toplists should PRTG keep in memory for access by the user
Finally you have the option to have PRTG resolve all IP addresses that it comes across using reverse DNS requests.
PRTG Traffic Grapher is an easy to use Windows software for monitoring and classifying bandwidth usage. It provides system administrators with live readings and long-term usage trends for their network devices. The most common usage is bandwidth usage monitoring, but you can also monitor many other aspects of your network like memory and CPU utilizations.