If I am understanding you correctly, you should be able to click the word "People" at the top left of the screen, then select the person you want in the "Find" box (a little below that toward the upper left). When you get a person showing in front of you, their info will be listed on the right section of the screen where you can edit it. No "Edit" button per se that I can see. You just type in there or correct in those boxes in the right side. (Name, Gender, Birth, Death, Marriage, etc.)
I haven't used earlier versions of Family Tree Maker before 2011 so don't know what you are seeing. I do know it took me a while to figure out how to get around in FTM when I first got it last year. I still don't use all of the features as I keep my tree on Ancestry.com and just use FTM for back up and reporting features.