Honestly, having the latest version of (4.3u) assuming this is a United States Wii, you are definitely good to go for a modified piece of happiness.
1) Check out this guide: LINK!
2) Follow this guide, maybe read it a couple of times to make sure nothing actually happens during the install process
*Note: Make sure to double check items as it says in the guide, for if there IS actually an error, you WILL know what to expect
3) After fully formatting your wii, rip a game from your new disc (normally bundled with your Wii) using one of the new loaders included
*Note: You'll learn about those as well
4) Post a sysCheck in case ANYTHING does not go as planned; however, do this anyways to make sure that further updates will not be required if you wish to do something else with your wii. Do this following this guide: LINK!
*Note: as noted in the guide of HOW to post a system check, please reply to this
thread instead of THAT thread lol.
5) Along with that, download this package: LINK! (This will double check your directories, and make sure that your wii folder's placing match that of the tutorial )
6) Wish you luck, and any questions you have, I or ANYONE will be happy to try to answer!