To run the USB backup system, you will need to mod your Wii system. It is done completely through software and no special tools are required. This guide will run you through the steps.
Select “Yes” when asked to Apply NAND permissions and download the patches from the internet server. Select “Yes” again when it prompts you to restore. When it completes, it will drop you back at the Homebrew Channel.
Run WBFS Manager with your external hard drive connected and select it from the dropdown menu in the program. Be sure to select the right drive because all data will be lost when it is formatted. After formatting, remove the external hard drive from your computer and plug it into the bottom USB port of the Wii.
Repeat this step for as many games as you want to copy.