Or, perhaps easier, in your timeline panel, to the right of the text properties, you'll see a little Animate flyout. Select all of your text and choose "Line Spacing". Then animate the vertical amount. Note, you will also need to animate the position of the layer to make it be centered.
- The Great Szalam
(The 'Great' stands for 'Not So Great, in fact, Extremely Humble')
No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.