For "unofficial" builds or devices not yet supported by the main Team Win team, the XDA Developers forums are the most reputable community resource. ZIP vs. IMG Files

Power off your device completely. Then boot into your existing custom recovery using the hardware key combination (usually or Power + Volume Down ). Alternatively, if your device is powered on and USB Debugging is on, you can use the command:

This is the safest source to ensure the file matches your specific hardware variant.