1. Add popup and outputText component at the end of your page (make sure popup is before outputText in the page structure)
2. Create bean binding for popup as well as outputText.
3. In the getter of outputText, launch popup programatically.
4. Set visible=false for outputText
Following code will help you to scroll to a specific row in a af:table on page load.
//Code to scroll to a specific row
RowKeySet ps = this.tableBinding.getSelectedRowKeys();
Also set the displayRow=selected for the table