In case you've never done anything like this before:
1. Use NUS Downloader to get the .wad in the instructions (Make sure Pack -> WAD is selected). Put IOS38-64-v3610.wad in the root of your SD card NOT in the wad folder.
2. Rename whatever the .dol is to boot.dol.
3. Put it in a folder (i.e. CIOSrev15Installer) and put that folder in the apps folder on the root of your SD card.
4. Insert SD card into the Wii.
5. Launch Homebrew Channel.
6. Select the CIOSrev15 installer. Choose IOS249, then WAD Installation. Let it finish.