Hi Aftab,
The listen to widget data source is for when you want to populate a dataview from a selection of a list on the same page. If you want a user to select a record from a list and then show a new page with that record, then you would pass that object to a new page.
Here is an example for a datagrid. You can add a button to your control bar and set it to open a page. Then when you create your new page you can add a dataview that is the same type of the datagrid. When a user clicks your button it will open your new page and pass the object that was selected in the list.
I would also check out the learning paths.
https://gettingstarted.mendixcloud.com/link/home
Hope this helps!