Connecting a preamp to computer
Connect clean +5V DC supply between "+5V" and the GND. Connect "Out" to the hot wire of the audio input. Connect GND to the ground side of the audio input. "Clean" means "taken from a separate battery" or a carefully filtered voltage. C1 can do the filtering if you have say 500 Ohm resistor in series with the +5V wire. 

Some common elementary precautions:

Do not expect your computer operating +5V is clean, it has much noise which can be heard as buzzes. Be sure that your computer's supply current doesn't go through any wire between your mic or preamp and the computer. It would cause more buzzes.