help required in creating custom dialog for install script msi project

I am new to Install Shield and dealing with an Install Script MSI project.
Now I need to create a custom dialog where I need to add two edit field where in user input the string and that string I need to set into some properties.

I followed the helpnet topic available at : http://helpnet.installshield.com/installshield16helplib/Dialogs_ImplementStandard.htm

I am getting confused about the steps.. can anyone help me getting some clarity what all should be needed for such a Dialog.:(

Thanks in advance,
Vikram