Press to select the Installer icon on your SpringBoard.
Press to select the Install tab at the bottom of the screen.
Press to select System froom the list of Categories.
Press to select Customize from the list of Packages.
Press the Install button at the top right hand corner.
Press the large Install button that appears.
Once the installation has completed you will be returned to the Categories list. Press the Home button to return to your SpringBoard. You will notice a new Customize icon.
Press to select the Customize icon to launch the application. You will see a picture of a chicken and then the menu will appear. If the menu does not appear you may have to try to relaunch Customize again. It may take 7 restarts before it works. This is a bug with Customize.
The Customize menu is basically a list of all the different images, sounds, and settings that you can change.
I will go through the first two so you can see how it works. Press the Dock Background button. You will see a picture of a dock. There is only one dock image because there are no Customize themes installed. If you install a theme then you will see an additional dock image in the list. Press the dock image to select it as your dock.
NOTE***: Follow this tutorial to install a Customize Theme: How to Install a Customize Theme
Now lets look at the second item in the Customize menu. This is probably the most important and useful feature of Customize.
Press to select Icon Display Order from the Customize menu.
Press to select Manual Reorder from the Display Order menu.
You will see two sections: Dock and Spring Board. To order the icons in these two sections simply press the handle on the right and drag the icon up or down.
If you would like to hide an icon press the Eye button at the top right. You will notice that the eyes to the left of all the application icons will be enabled. Press an icon and its eye will disappear. This means that the icon will be invisible. Be careful with what you make invisible. Press the Eye button at the top right to exit out of this mode.
Most of the other items in the Customize menu are self explanatory. When you select the item you will see a list of all the images or sounds from the different themes you have installed. Just select the one you would like to use.