PowerPoint uses its own fiendish naming scheme for all your objects. Name like Rectangle 5, TextBox 4 etc make perfect sense until you have to animate them and then you have real problems trying to identify specific objects. All you have to do is rename them according to their appearance or purpose and you’ll have a much easier time creating animations.
An object named something like “Black Heart” or “Red Star” is a lot easier to deal with than “Heart 4”. To rename an object, click the current name in the pane and replace the text.
There’s nothing wrong with having cluttered PowerPoint slides—you just need to know how to work with them easily.