This is a multi-stage cache. You will need an NFC reader app on your phone. When you arrive at the Posted Coordinates, find the NFC attached to the light pole skirt (put your phone next to the black duct tape with your NFC app open), which will give instructions to reach one waypoint and then to navigate to the cache. If you do not have an NFC reader, go to the Certitude (No NFC) Waypoint, and use the keyword obtained with Certitude to get instructions to the cache
You can validate your puzzle solution with
certitude.