Cleanup of Backups

Hello,
On my Acronis page I show 12 previous backups. All have identical names. My 1Tb external drive is getting full and I need to make space. How do I know which to delete from the Acronis page. Obviously, I can delete files from my storage drive, but I think it is better to let Acronis do the clean-up. Before, I have deleted backups by date, but the backups are still listed on the Acronis page. Please advise.