newbie_cctv2018

Hi 1st post here so go easy please I've recently bought the iegeek 1080p bullet CCTV camera. Set up seemed to go ok, I've installed the app on my android phone called "camhi" version 5.1.53 Whilst at home my phone connects to the camera via the app, but when out of wifi radius I can't connect to the camera. Am I missing anything obvious ? I have left the camera hardwired to ethernet cable, thinking this will give a better connection than relying on the wifi, which is strong anyway. Also thinking ahead is there bette apps/software I can use for this camera ?? Any tips on recording direct to NAS drive, much appreciated. Thanks for reading & I hope you can help.