Animating digits

Hi All,

how is everyone doing? Fantastic over here. AND even better if one of you could help me with the following. When looking at the attached, what Im``trying to do is, animate some digits, which are randomly entering the screen from the left (maybe I can define an are with a mask), then in step two form a large digit (square quadrat) and after some time leave the srceen randomly again to the right. But when I mean randomly, it mustnt necessarilly be random, important is that the digits come in consequently.
thanks for any advice in advance.