A few more details, but the process is pretty straightforward. Most people have problems with Windows drivers more than anything else. And you need adb and fastboot, which are generally part of the Android SDK but you can get them separately.
- adb push LATEST supersu.zip to device while in ROM
- adb reboot bootloader (boot into the bootloader)
- fastboot oem unlock (unlock the bootloader)
- fastboot reboot-bootloader (reboot back into the now-unlocked bootloader)
- fastboot flash recovery recovery-of-choice.img (flash twrp/cwm)
- When done, use volume keys to select Recovery, Power to select
- Flash SuperSU zip (once twrp/cwm boots, find the option to flash zip)