Got this off of amazon and used some extra gopro parts to mount it.
Octo Mounts Universal Smartphone Holder Adapter Kit. Compatible with Any Tripod, Action Mount or GoPro Mount Accessory. Compatible with iPhone, Samsung Galaxy, Android, Blackberry, Pixel, and HTC
https://www.amazon.com/dp/B075MMSXDM..._WxFwDb245RDCF