To flash the assembled software into the microcontroller, you need a programmer software and an in-system-programmer.
Atmel Studio allows you to program Atmel microcontrollers. Atmel also produces an USB in-system-programmer, the AVRISP mkII.
Of course there are also third party in-system-programmers available.
All fuses keep their default state except the Brown-out detection which is set to 2.7 V: