Creation of buttons in toolbar & option in menu

Hi

I want to place a button in CATIA toolbar and whenever i click on that button, a dialog box need to be appear on the CATIA GUI. for this, i want to develop DLL using CATIA CAA RADE. how to do this. how to integrate this dll with CATIA, so that whenever i click the button, the dialog box will be called from DLL.

Similarly I want to place an option in any of the CATIA menu and whenever i select the option, a dialog box need to be appear on the CATIA GUI. for this, i want to develop DLL using CATIA CAA RADE. how to do this. how to integrate this dll with CATIA, so that whenever i select the option, the dialog box will be called from DLL.

What is workshop, workbench, Addin and command header.

i request you to please reply as soon as possible,

Thanks

Rajakumar K