The easiest way to see stats by position is with a report like Summary > Group by Position. This will show all of the active player's hands grouped by position.
As an alternative, if you want to see all hands where the button 3Bet, regardless of who is on the button, you can do that with
My Reports.
Create a new 'Hand' report.
Click on the Filters link and choose 'expression filters', and turn off Filter on Active Player. This will show every hand from every player's point of view.
Now you can apply Simple Filters for being on the button, and making a 3Bet. This will show you every hand where the button 3Bet, no matter who they are.