Hold , , , and to reset TWiLight Menu++ Settings.
Hold SELECT to directly go to the settings menu.
Hold to load the menu or the last ran ROM, depending on if autobooting the last ran rom is enabled.
TWiLight Menu++ has 6 different themes you can pick from. These are alternative menus which all have different designs, some of them having completely separate navigational styles.
TWiLight Menu++, as the name implies, is just a menu. It doesn't actually load the ROMs itself. Here are the manual pages for the ROM loaders:
Want more information on TWiLight Menu++? Check out the Wiki: