If you want to see what is the column number(Index) in a webtable. Please follo the below navigation.
1. Launch QTP
2.Launch gmail and login with your credentials
3.Make sure that you are in Inbox" page
4.Open the QTP and hit "F3" button on Keyboard(Recording-->ON)
5.Wait for a moment(2 seconds)
6.Hit "F12" button on "KeyBoard"
7.You might be observing one "HAND" icon
8. Show this icon on "Webtable" i.e "Inbox" page
9. Now you can get the Entire Webtable structure with all required rows and columns information.