This tutorial will explain you how to install WADs on your Wii with Wii Mod Lite. The WAD manager of choice is Wii Mod Lite, but there are others such as YAWMM.
2. Choose `Wii SD Slot` or `USB Mass Storage Device`, depending on whether you want to use an SD card or USB drive. 
3. Select the WAD you want to install. In this example, we're installing the patched IOS needed for [RiiConnect24](riiconnect24). You can mark multiple WADs by pressing the + Button. 