I think it's going way to fast, so you can re-read the steps below. Without time pressure and above all: without annoying circus music.
#1. Create a new text layer in a composition.
#2. Left align your text and drag it to the center.
#3. Add the effect “Slider Control” to your text.
#4. Animate “Slider Control” from 0 to 100.
#5. Select “Character Offset” in the Animate menu.
#6. Alt + CLICK on the “Character Offset” stopwatch.
#7. Type this: