For Android Wear 2.0 or later: you need to install Golf Pad on your phone and smart watch. Open Play Store on the watch and choose Golf Pad from the tab named "Apps from phone". Then enable the smart watch link in Golf Pad preferences on your phone. Make sure that the watch is connected to your phone's bluetooth. The first time you use the Android Wear watch with Golf Pad there may be a delay to the distances showing up on the watch. Do not be alarmed, this only happens the first time you use it, after that the distance and score updates will be instant.
For Android Wear 1.X you do not need to install the separate app on the watch. It will sync automatically, though it may take up to an hour during the first use.
For more information and troubleshooting please check this page.