How to Add Batch Animations

Select all the elements that you want to animate. 

Right-click > select Group

Select the Group on the timeline > Click on the Flash icon on the right panel

The flash icon opens the Batch Animation properties that you can animate.

By default, they are all set to zero (0).

Changing the value of each property gives you additional options to adjust Speed and Randomness

Speed

How fast the elements animate

Moving it closer to 0% slows it down while moving it closer to 100% makes it faster

Randomness

Setting the Randomness value to 0% makes the elements move at exactly the same time

Setting it to 100% makes them randomly animate unsynchronized. 

You can also animate different properties (Opacity, Angle, Top, Left, Scale) at the same time.