1. Write your text. Add a lot of text, more than you might need, just to see the effect.
2. Add a circular path, centered in the scene.
3. Open text properties and set the Path dropdown to the circular path. The text is now on the circle, and you want enough text to loop around the circle a few times.
4. Turn on the 3D switch for the layer.
5. Use the rotate tool or the rotation controls on the layer to rotate the layer away from you along the x axis. The text should now look like it is in a circle, on the "floor".
Under the text properties, choose the "animate" flyout and choose "enable per-character 3D". Then go back to the same flyout and choose "rotation". Adjust the Animator 1 rotation property to 90 on the x axis. Your text should now be "standing up".
6. Deselect Animator 1 (important).
7. Go back to the "Animate" flyout and this time choose "position". This will create a new "Animator 2". Adjust the position inside to a negative z position... I chose -500 for my example.
8. Go into Animator 2->Range Selector->Advanced and set the "shape" popup to "ramp up". Your text should now be a nice helix shape.
9. Once you have the slope the way you like it, go back into Animator 1 and adjust the z rotation to orient the text properly along the path.
10. Animate to taste.