modmii is a computer program which download what you need to install and launch on your wii based on your answers to specific questions.
It also generates a guide/tutorial specific to your answers.
After answering the questions, it will download everything (IOS, cIOS, Homebrew, etc.) that you need to copy to an SD card. then follow the generated guide.
before following the guide, in the wad folder you can delete the "USBLoader forwarder" if you don't want to install it.
It's a generic forwarder, looking at multiple usual locations for multiple USBLoaders. It loads the first one it encounter, not necessarily the one you want.
keep everything else, and follow the guide step by step.