Hello Hari Chennareddy!
For clicking on menu item you should use related object or text object (with or without Area object). For detection popup dialog you should find some specific to this dialog text or image object and use Exist method. Also you could create special view for this dialog.
We created simple test where we open notepad.exe application, click on help menu item and then about item, check the popup dialog, click OK button and finally close the application. Execution takes 3 seconds on our test environment.
Also you could find some information and code examples on our tutorial page: https://www.zaptest.com/tutorial
Hope this will help you!