Getting the right IP bullet Cam?

[Immolation73]

Hi everyone, just a bit of advice really.

I bought a Floureon CCTV bundle with a NVR (branded Floureon) and 2 ip wireless cameras also included.

I'm wanting to buy another camera as its a 4ch system but cannot find which camera I should buy?.
I bought a black floureon camera last week but it only works with an app and won't connect to the nvr.

Any advice would really help

Neil