First, copy the BrushedAluminum directory tree (and files) into your /centrafuse/skins folder.
In Centrafuse, from the HOME screen, click the Utilities button. On the UTILITIES screen, click Settings.
On that first screen, you should see the "Skin" option. Click inside the text box that probably says "848x600", and a window will pop up allowing you to choose another skin. Hopefully "BrushedAluminum" will be an available option.
Once selected, click Next... Finish, then when prompted, click OK to save your changes. The new skin should load immediately.
Some people have reported that when loading the skin, the text on the left-side buttons appears over the icons. The skin is designed to ONLY show the icons and no text. Exiting then restarting Centrafuse fixes this.