Create game and integrate Facebook SDK native on Android and iOS?

Hi,
I’m making a game for Android and iOS and i’m currently trying to integrate Facebook SDK to share score and invite friends. Since there aren’t any good tutorials and the Documentation I found on Facebook is quite useless on integrating Facebook SDK on Unity for Mobile, I thought and I want to ask you… Is it better to make the game and finally add the Facebook SDK native on both OS? Is this even possible? Cause I think the Documentation for native Android and iOS is better.

P.S.
I still want to make this work with Unity since it would be much simpler. Currently I can login but I have a problem on sharing the score. The problem is its not posting the description I wrote and I can’t find a way to upload a ScreenShot of the game and showing the score with it (Using FeedShare method). And thats only for now… I don’t know in what trouble i will go when I will try to make the invite friends and the Leaderboard. Any suggestions would be thankful.

ive seen plugins in asset store and like this, GitHub - NicholasSheehan/Unity-Native-Sharing: A Unity plugin to open native sharing dialogs on iOS and Android, primarily for text and files
never used then yet though…