Hello Krishna,
I assuming the Delete button is a standard button, right?
My suggestion is to write the following script and attach it to the delete button:
session.findById(<id of the tab from where the delete button came>).select();
session.findById(<id of delete button>).press();
// now the popup should come up
// script to confirm the popup
// optional: navigate back to the original tab
return true; // prevent the standard action of the delete button to execute, which we have already done
The whole script should be easy to record (except for the return true;):
1) Create the script
2) Switch to Original Screen while leaving the scripting editor open
3) Start recording
4) Record the above steps.
Best Regards,
Clemens