You have to unlock your bootloader at htcdev.com then flash custom recovery in bootloader, flash superuser binary in recovery, install Busybox installer app from the Play Store, and install superuser from the Play Store as well.
I have a guide posted in this section that should be pretty easy to follow, but there are no one click root methods for this device. Give my guide a try and if you have any problems post them there and I'll do my best to address them in a timely manner. The whole process isn't too difficult, but please let me know how it goes for you.
*Sent from work early bcuz some1 4got teh NSFW tag*