how do I add place names to events in iPhoto 11

How do I add place names to events iPhoto 11 version 9.2.1, I can do a single picture at a time but when you have a 100 or so it's going to get tedius.

I have found messages via google that tell me how to do it but it dos'nt work.

I select the event I want to locate. then I click "cmd i" to get the info screen up. Then at the bottom of the screen is a picture of the world and a box next to it where I think you should type in your location, but that just takes me to a map of the USA and I can't do anything.

Help please, what am I doing wrong.