Post Gui Call Flow

I have read the asterisk future of telephony book and found it very helpful. I was able to setup the basic examples in the book and I have my Asterisk system up and running for the most part. My system is very simple. I have two grandstream phones; a budget tone 101 and a GXP2020 configured with two extensions. I connect to a SIP provider (broadvoice) for outside calls.

After getting familiar with the system, I decided in d/l, compile and install the asterisk-gui application. I like the interface, however after reconfiguring my system using the gui interface, I no longer understand the call flow.

In the book phones were setup in sip.conf and dial plans in the extensions.conf. However, the gui has created a sip file that is practically empty and it appears that the phones are setup in the users.conf file. The extensions.conf file is much more complicated now.

In any case, I am trying to figure out how call flow works with the post gui setup. For example when I want to make a call from one sip phone to another which conf files are accessed in what order? How does it determine the context to use in the extensions.conf file?

Any guidance would be greatly appreciated.

Thanks in advance,