Many ways to do this. One of the simplest and quickest (cpu-wise) is to use the placement function in the text generator dialogue. Create the text. Drag the keyframe to the left, to the point where you want the text fylly scrolled in. Create a new keyframe at the far left and set the x value to something like 1.5 (experiment). If you want the text to stand still for a while, creat a new keyframe wher you want to movement to re-start. Then at the far right, create yet another keyframe and set the x-value to MINUS what you had in the far left keyframe.
This text will scroll in from right. Stand still for a while and scroll off to the left. Very nice effect, and readable too, because of the short stop.
Remember to make all ajustments to your text before you start creating keyframes. Saves you having to edit all of them.
Tor