If you want to use cheats and don't know how, this guide will tell you exactly what to do.
1. In the Cheats forum, search for the game you want. When you find a thread with codes, copy the codes and paste them into a .txt file on your computer (right-click your desktop and click New > Text Document. Or, click Start > All Programs > Accessories > Notepad, at least for Windows XP). Also in the thread is a 6-character (4-character for WiiWare and VC games) code. Copy this and use it for the text documents title.
You can also find codes by googling "gecko codes" and clicking the first link. On the site, you can simply download the entire code list as .txt files instead of having to make the file yourself.
2. Download Code Manager in the link below, then unzip it to your desired location.
3. Run the program. Click File > Open TXT file and browse for the .txt file you created earlier. Enable the codes you want to have, then click "Export to GCT". Click "Store" to store at the desired location.
4. Download Gecko OS in the link below, then place it in the "apps" folder on your sd card, and place the .gct file you just created in the "codes" folder on the root of your sd card.
5. Insert your sd card into your wii, and run Gecko OS via the Homebrew Channel. Go into the settings menu, enable Ocarina cheats, then load your game or channel.
Note: Gecko OS is not a backup launcher, thus, you will need either cIOSCORP or a modchip to load cheats into a backup. There is, however, a cheats loader embedded into NeoGamma, a backup launcher.
For NeoGamma cheat loading, again place the .gct files in the "codes" folder on the root of the sd card. Then go into the options menu in NeoGamma and turn on cheats using cIOS, then set the hook type. VBI may be a good choice if you're unfamiliar with it.