Atmel studio is a powerful tool for making AVR programs, but writing a program is the first step. To use your program you must make a circuit and transfer your code into microcontroller. You can program your AVR from Atmel Studio by the use of STK500 hardware. Why you cannot program MCU directly from computer by a cheap hardware like PIC microcontrollers? The answer is that to transfer your program to IC you must use SPI connection, but there is no SPI port on the PC. There are several software that use RS232 port as SPI, but you cannot program your AVR directly from Atmel Studio like them. Here I introduce you a software that simulates STK500 hardware on the PC and sends data to microcontroller using RS232 via a simple and cheap hardware. Note that using PC RS232 as SPI port is slow and programming the chip will take more time than a STK500 device.
To make the hardware you need:
Solder resistors to pins 3, 4, 6 and 7 of DB9 connector, solder N pin of diodes to the other end of resistors and solder the other leg of diodes to the pin 5 of DB9 connector. Solder cable wires between resistors and diodes and pins 4 and 5 of DB9 connector. Solder other end of cable wires to female part of Pin header.
Looking at the circuit diagram will help you a lot while making the hardware.
Note that RESET pin of microcontroller must be connected to +5V via a 10K resistor in your circuit.