All you should have to do is select Rectangle 1 or whatever shape you want to rename, press the enter/return key and type in a new name. If it does not have a stopwatch and you can select it in the Effects Control Panel or the Timeline you should be able to rename it:
Just be careful with your names so you can figure out what you are doing in 3 months when the client wants to redo the project.
In the long run, giving custom names to such things now can lead to confusion for you later. I wouldn't do it.
Thank you so very much, sir. I appreciate it.
Dave LaRonde: In the long run, giving custom names to such things now can lead to confusion for you later. I wouldn't do it.
Not only would I respectfully disagree with that, Dave, but I would strongly encourage otherwise. If anything, descriptively labeling the shapes helps keep organized and avoid confusion. (e.g. Ellipse, Circle, Large Circle, Square, Rectangle, Dot, Hexagon, Diamond, Pentagon, Pentagram, Star, etc...)