I can't download previous purchase
I can't download the musics that I got, cause I formated the Ipad.
iPad 2, iOS 6.1.3, I lose my musics
What happens when you try ? Whether you can re-download your previously purchased music via the Purchased tab in the iTunes store app on your iPad depends upon what country that you are in (it's not possible in all countries), and whether it's still in the store - if it's not showing in the Purchased tab then you will need to sync it from your computer's iTunes
The 'automatic downloads' page that you posted from only applies to future purchases e.g. if you turn it 'on' on your iPad then any music that you then buy on your computer's iTunes should automatically download on your iPad.