Well you can get started with the Camera API(updated to Camera2 API) and the CameraX API which will help you with photography on Android devices.
Regarding storage, I suggest that you start with what is provided in the Google Documentation and work your way up from there.
The best way to learn is by using the Android Developer Guides as a base and StackOverflow posts to clarify implementation problems and troubleshooting.
Cheers!
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