For this tutorial, you are going to learn a way of using the 3D Transform to create some 3d stuff.
Step 1: Open up a new 500x500 document with a white background. Now create a new layer and go to Filter > Render > 3D Transform
Step 2: In the pop up menu, click on options and uncheck show background. Press OK
Step 3: Select the cube tool (or press m), and draw a cube out on the left side of the checkered image. Now press A to select the direct selection tool. Click and hold on one of the top corners of the cube, and drag it to slant it. Create two more cubes, doing the same thing as you did to the first one.
Step 4: Press R to select the trackball tool, you will notice the background behind your cubes will turn black. Now, click and drag your mouse downwards until you have flipped the cubes over. You will know when the cubes have flipped because they will no longer be checkered, but will appear as white 3D cubes.
Step 5: Press OK to complete the 3D transform. The cubes will be created on your new layer, and you can move them around and rotate them however you like. Add a few more efects, and you can even do images like this: