I try to download maps for MCPS3 edition (Mincraft PS3 edition)?

Where are you getting these maps? You can't load someone's save and get their content so I don;t get why you are talking about save data utility, you can only play another persons levels if you are on their friends list and you are playing at the same time they are ( they have to invite you )

anything you do get online when playing will be in your game data as a downloaded item, not in a save file

No on the internet there are links to maps to download and put on a usb drive. The usb drive is then put into the ps3 and with special folders on the usb, you can save the maps you got off the internet into the saved data utility which the maps then should be showing up in the mincrafte menu where you select your world to go into