I just downloaded the laest AE trial. I looked on Adobe TV for some training.
I swear I am following the tutorial exactly and I do not see any animation when I click the play button to preview the animation. I can barely see any motion when I drag the timeline bar, but nothing happens when I press the play button. I see the timeline red line move and loop, but not animation.
My back hurts sitting here trying to find out why for so long.
The tutorial that you linked to isn't the best for someone just getting started.
Try the steps in this tutorial ("Basic workflow tutorial"). If any of the steps don't work for you, write back.
I also recommend working your way in order through the items under the "Getting started" heading on this page.