I want to root my Moto G2 (running Marshmallow). I've never tried this before, so please tell me exactly step by step.
Download the latest SuperSU zip file and save it to your device at the root of the internal storage.
Enable Developer Options on your device by going to Settings → About and then tapping the build number 7 times. Then go into Developer Options (again under Settings) and enable USB Debugging.
Unlock your bootloader. This will wipe your data.
Connect your device to your PC, open a Command Prompt / shell, and run:
adb reboot bootloader
Wait for the device to reboot, then run:
fastboot oem get_unlock_data
Enter the resulting code at this Motorola site (making sure to format it as it says).
Enter the resulting key from that site in another command:
fastboot oem unlock <key>
Download the latest TWRP image to your PC and flash it:
fastboot flash recovery twrp-<version>-titan.img
Reboot your device, repeat step #3, then run:
adb reboot recovery
From TWRP, choose Install and then select the SuperSU zip file you obtained in step #1. Follow the prompts to flash the package and then reboot your device.
You are now rooted!