First you need to download and install the dolphin emulator
Then you need to find rom files, you can use https://thepiratebay.org for that.
For wii games you probably want to just buy a wiimote and nunchuk, for local multiplayer you need more than one controller, luckily it's relatively cheap (30 to 40$).
The wii sensor bar is just two infrared lights, you do not need the original sensor-bar for that.
You can use your keyboard to play gamecube games, you might want to use a controller instead, doesn't have to be game-cube controller.
Then you need to find rom files, you can use https://thepiratebay.org for that.
For wii games you probably want to just buy a wiimote and nunchuk, for local multiplayer you need more than one controller, luckily it's relatively cheap (30 to 40$).
The wii sensor bar is just two infrared lights, you do not need the original sensor-bar for that.
You can use your keyboard to play gamecube games, you might want to use a controller instead, doesn't have to be game-cube controller.