Adding an animation to a content block can be good for when you want to add a form of transition an element into view. It could make certain elements fade and move from one position and become completely visible in the final position.
Start by selecting a content block you wish to add an animation too. Go to the Advanced tab on the right side of the editor and you will see animation drop-down menu options.
Once you have selected an animation, more options below the drop-down menu will appear which then need to be set. Editing the Speed would be how fast the animation takes to complete from start to end. Editing the Delay would be when you first begin to load up the specific page how long until the animation will then trigger for the content block to appear.
Once you have set these settings, you can test by viewing the publication, the animation should then work along with its delay before starting the animation and then how fast the animation goes on for.