After installing Personal Firewall, you will see many popup windows. These windows allert you about either incoming connection from remote endpoint to your computer, or outgoing connection from your coputer to remote host.

A rule may be created for certain connection if you enable create rule checkbox. Rules are located on Rules tab on main window.

After packet is received, firewall compares packet data to first rule in the list. Second rule is compared, if first one does not match, and so on. Once rule is found, the program applies action to the network packet. The program will alert you if rule is not found.