You have several options for stringed electric and electroacoustic instruments:
- Plug it to an amplifier.
- Use a 1/4" to USB instrument cable to connect it to PC/Mac.
- Use an audio interface.
- Use a standard 3.5mm adapter jack. This only works if your computer has a separate jack for mic and headphones (E.g. not on MacBook Air).
You can find piano set up instructions here.