There are several ways to do this. Here's one way.
Let's assume you wish to run the text from right to left across your slide.
1) Place the text to the Left of your slide - make sure the right most end
of the text is out side of the viewing area.
2) Use the Enter > Fly In > From Right animation
3) Adjust timing so that the text enters and exits slowly enough to be read.
Thanks Sandy! Almost functioning... the problem is that I have a very long
text which need to be read as it slowly moves into the picture, it does fly
in now, but it comes like a block of text and not one line, what can I do?