Just days after the Droid DNA was announced, and with a few days yet before retail availability, Rootzwiki devs dsb9938, Dr_Drache, Dees_Troy, and utkanos have already achieved what I like to call the Modder's Trifecta: root, custom recovery and a custom kernel. While this still doesn't achieve S-Off for the newest HTC superphone, dsb9938's achievement gives DNA owners everything they need to flash custom ROMs before they even take their phones out of the box.
Once you unlock the DNA's bootloader via HTCDev's unlock tool, you'll have to flash your custom kernel via fastboot. Once you've done that, you'll be ready to flash either TWRP or ClockworkMod recovery via fastboot, which you will then use to flash SU.Busybox.Installer.zip from this thread to gain root access.
Until S-Off is achieved, you will not be able to write to the system partition while booted into your ROM. You will have to be in recovery in order to do so. For example, your favorite root-enabled file explorer will not be able to write to your system partition, meaning you can't delete system apps that you wish to replace manually. If you want to flash your favorite inverted or otherwise customized system apps (Calendar, for example), you'll have to use a flashable zip to do so.
For detailed instructions, please consult the following threads in our Droid DNA development section: