Gigamax controllers often use generic chipsets that are compatible with universal gamepad drivers. You can find specific driver packages for popular models on reputable third-party driver sites:

If your controller isn't working after plugging it in, follow these steps to manually update the driver: Gigamax GP-8080 Bluetooth Gamepad - Vibration Feedback

Simply plug the USB cable into your PC. Windows should notify you that the "device is ready to use" within seconds.