The easiest way I know how is to first create a stagger animation that [I]
removes [/I]the text, so in your case, start with Alpha at 100, and fade to Alpha 0. Once you have a stagger animation that fades out the text, drag it into your scene director on the text object's track, then right click on the stagger animation and click "Reverse Direction". This will reverse the entire animation so that it fades on, starting from the last character and ends with the first character.
Hope this helps.
Jeff Rietman
#XPression