Android Unity App With Facebook Integration - Canvas Problems

Hi. So, I'm making an app that will have Facebook integration such as score leaderboards, post to feed and send request to other players using Facebook SDK for Unity. The problem I'm having is that for people in facebook to receive the notifications of the game, my facebook app has to have a canvas url set up .But the problem is my application won't be a facebook application just an android app with facebook funcionalities. So, when a player receives a game request or posts something about the game on their feed and someone clicks them, facebook redirects to the canvas of the game that will be empty because I don't have a facebook game. How can I get around this? Can I make the facebook canvas redirect the page to the Google Play download page of my game or something? Or for me to use the feed and game request options I am required to have a facebook version of the game? Any help concerning this matter will be very welcome because I'm searching online and I haven't found any answers. Thanks in advance.