How to use APD

APD (Application Performance Dashboard) is a very useful widget in NPC.  It allows the report designer to create a crosstab-like report showing the performance of a single set of networks when connecting to multiple applications.  The nice thing about this is that application traffic can be consolidated into a single view that is easy to troubleshoot.
The first thing you do is determine which network group to focus on.  If you've followed my best practice and created and 'All Sites' group, this usually becomes a great group to use for the network.
The next thing to do is to configure which applications these networks should connect to.  In order to see which of your SA configured applications are your front end, you can go to SA and look at the performance map filtered by the 'All Sites' network group.  The applications listed with the highest observation counts are probably your front ends.
After that, you can configure the back end applications.  The easiest way to do this is within the wizard itself.  Click 'add second tier' and look for the application with the highest observation counts.  APD counts a second tier application whenever it sees the server(s) of a front tier application acting as a network and connecting to the second tier application.  The same applies to a third tier application.

If you have a load balancer that only changes the destination address (and not the source address) on incoming packets, the true second tier application will appear as a first tier application.  In that case, add the true second tier application as a first tier application to the APD.