Driver Install instructions for ASUS NVIDIA GEFORCE 1070GTX for Ubuntu 18.04 Bionic Beaver

any suggestions for what driver version of ASUS NVIDIA GEFORCE 1070GTX to install for Ubuntu 18.04 ? been trying to get nvidia-smi command to work, tried lots of different methods, but still get this error:-

NVIDIA-SMI has failed because it couldn’t communicate with the NVIDIA driver. Make sure that the latest NVIDIA driver is installed and running.

any help much appreciated