Configuring a browser embedded application is pretty simple, and requires three things:
The name of the server, or servers that the application communicates with on the internal network
The TCP/IP port or ports that the application communicates on
The initial URL of the application
If your intention is to publish Citrix, then this is easy, as the built-in template includes the standard ports used by Citrix: 1494, 2598 and 3389. Otherwise, if you are well versed in the application you intend to publish, you should already know these parameters. If not, the application's administrator or owner should know this. Sometimes, no one has a clue, and in that case, it should be possible to contact the application developer or vendor and find that information. If all else fails, it's also possible to simply set up a Network Monitor capture (a.k.a. Network Sniff) with an application like the free Microsoft Network Monitor or WireShark. A quick recording on a client...