To play it you'll need
- the boot.dol ( the game itself )
- A way to load that file and play it
For ways to load the game, you'll either need a wii with the ability to load a dol file ( the best scenario is generally having the homebrew channel installed ) or you could use an emulator on a PC.
See wiibrew.org to review your options for installing the homebrew channel.
If you don't have a wii, but have a reasonably specced PC you may be able to use an emulator like Dolphin-emu.