Flash Arduino Micro code on Atmega32U micro controller
To get your chip to respond to the Arduino environment over USB you need a booloader (some extra code) to be running on the Atmega32. 

To install the bootloader you can use another Arduino as a programmer to the ICSP pins (or any other AVR ICSP programmer).
This procedure and description from Sparkfun for the Arduino Pro will help you.   

This may help you understand the ICSP aspect, again from Sparkfun.