Quote Originally Posted by joebats72 View Post
1)Do signal and slot functions get automatically generated in the code or do they have to be manually added?
You have connected a signal that already exists (clicked()) in the code of QPushButton to a slot that already exists in the code of QTextEdit (clear()). You don't have to create these routines. Designer has generated the code to connect the two pre-existing methods. You can see that code in a file ui_mainwindow.h (a name matching your source file) that is generated when you build your project.

You have to declare any new signal that you wish to create for your own QObject derivatives, and let moc generate the code for that signal.
You have to declare and implement any new slot that you wish to create for your own QObject derivatives.
Open Qt Assistant and read about Signals and Slots
2)How would I start to create additional dialog boxes to be attached to the menus? For example, if I want to invoke an open file dialog from File->Open, how would I do this?
Open Qt Assistant and read the Standard Dialogs and the Application example. These examples cover everything you have asked, and there are plenty of others.
3)How can I add additional dialogs to my menus using QT designer?
Qt Designer designs a single UI element at a time. You design the new dialog using Designer and write code to create and display it from other places.