You need an internet connection on the wii that's setup and working.
Then you need 1000 wii points which can be bought for 10$ on credit card, or 20$ on a 2000 wii points card (it's only 2000 wii points cards atm). Then, when toribash is out in your area, (if you europe, it's already out), look for the title toribash under publisher Nabi Studios, and click download.