Nice job on your first try!
CS4 is even more complicated than PSE, though I would love to be able to afford it (I have Elements 6). I would agree with cheery97 that one layer is behind another that's why you are not seeing it. Below is a screen shot of my user interface which is very similar to the one in Photoshop. The layers pallette is in the lower right. It consists of three layers, Dash, the text and the background "sign". If I moved the sign above the test it would be like it was "laying" on top of it and you would not be able to see it.
The other thing is to make sure the layers you want are active by making sure the "eye" on the left side of each layer is visible. If you cna't see the eye you will not be able to see the layer.
Keep taking tutorials. I'd recommend the ones on
www.planetphotoshop.com. Start with some of the older ones as they may be simpler in scope. If you're not familiar with digital photography terms it may be a good idea to do a google search for a site that gives defintions of them. Lastly post here, being as specific as possible, with you questions and the great people on this board will help you out.