Substance Painter should be set-up to the specifications required for your end rendering engine (typically Unreal Engine, Unity, V-Ray, Arnold, Octane or iRay). This ensures parity between substance painter and your rendering software, so that what you see while working in Substance Painter is the same as what you will see in your rendering software. You should test your work in your rendering software before finalizing it.

Seen below, we have set-up our file for Unreal Engine, the key being the normal map format (DirectX), which has an inverted green channel of the normal map texture (as opposed to OpenGL like you would use in Unity).