If you're coming from Big River Beach, take a left to stay on Big River Road, which will eventually lead you to High Chutes Road and Old Haul Road. Alternatively, go right to follow the road along the river, which will take you to a bridge crossing Big River and, eventually, the Big River Lagoon.
If you're approaching from High Chutes Road or Old Haul Road, simply go straight to continue your journey to Big River Beach