Facebook instant game async turn based multiplayer setup

Hi everyone !

I would like to develop an app playing from messenger, games just like "word with friend" or things like that. After a long time looking through what is existing (facebook SDK, firebase, gamesparks, playfab), I found out that I should go for "Facebook Instant Game SDK". From that, I was wondering if there was a very simple way to setup a multiplayer.

The goal is pretty easy, one player challenge a friend or a random person by playing a round, score the most point, the other get a notification and play whenever he wants. Sending a notification to the first player, and so on till the game is won.

There's a tutorial on web but it is not unity specific, and I have difficulties to find my way out in that.

Can you guys help me ?

Thanks a lot !