To use this app you need two android phones.
So , before installing this app you have to install a other app in your first android phone which you want to make as camera . Steps are following for camera app:-
1.Install the CCTV mobile app with this link : https://play.google.com/store/apps/details?id=mobile.cctv.camera in your first android phone.
2.after installing ,open that app, an ID will generate , note down that id .
3. next after clicking OK , it will ask the permission for the camera , allow them and camera will be open , there is option to select rear and front camera .
4.make sure phone will never lock and camera is always open. It will send footage every 30 seconds

Now , after installing above app , need to installing this app in your second android phone. Steps for viewing FOOTAGE captured by camera app are following:-

1. install this app
2.open and run the app
3.enter id , which you noted in CCTV camera app.
4. and click refresh button you will see the footage.

every time you click refresh , you will see updated footage .Make sure you click after 30 seconds.