Although the above result might not impress you, the tutorial describes a technique widely used to create 3D effects. The general idea is to create a "height-map" for the rendering. This "map" is a black and white layer where white is high and black is low. So a fade from white to black would mean a slope from high to low.
What we first need to do is to create a new layer. Start out with a completely red one.
You should now have a result which looks something like this
Make a circular selection. Hold shift down to do a perfect circle, if you want a perfect circle. Right click on the image, click Select and then Save to channel. Click the "Channels" tab in the Layers dialogue and duplicate the channel you just created.
Now select the top mask and right click the image and choose Select->All. Now choose a gaussian blur from the filters menu. Experiment with the degree of blurring. Aim for something like in the screenshot below. When blurring it's often good to do blur several times with smaller and smaller radi, like this:
16,8,4,2,1Experiment yourself. Halving the value each time reduces noise and produces a allround prettier looking bump map.
Now go back to the Layers tab, and select the red layer again. Right click and goto Filters->map->Bump map.
Select the channel you blurred before and play around with the knobs. Do the bump map and return to the read layer with the bulp on it.
Return to the sharp Channel and right click it and select "Channel to Selection". This will return the original circular selection. Return to the red image and use Select->Invert. And then Edit->Cut.
Now all that is left is to add a drop shadow:
Final hints: Read the next tutorial on doing rounded corners, use the result as a channel, blur it, and use it to do bump maps after. You can use any shape to do bump maps. Do also try using the Lightning effects filter instead of bump map, but apply the same procedure.