Trophy Help For Version 2.03

So I've finally got around to deleting my Save File on PS3 and I have a game save back up of tables that I accomplished all goals for trophies. I'm wondering how do I add my old game save to overwrite the existing one ? My save data is on a memory stick. Just asking for help because I don't want to do anything silly like deleting new save data I should mention that I've never done anything like this before on my PS3.