Since smartart is a collection of shapes that is grouped, it can be quite challenging to animate a smartart in a way that you want. PowerPoint out of box allows you limited flexibility in the way you can animate sub parts of a smart art.
Let us assume the following smart art
Say if I want to animate this so that the first Level 1 appears, then the equivalent Level 2 appears and so on.
But the default animation options will give you the following:
This obviously does not fit into our flow. So instead of using the Level based animation, we can do the one-by-one animation and then customize the animation further to fit our need. The below video shows the customization that will allow us to animate the smartart as per our requirement.