Adding Halo5 to xbox app after windows reinstall

So I’ve recently had to reinstall windows and I am wondering how I can get the Xbox app to recognise/install my Halo 5 Forge folder/game. I already have Halo 5 Forge downloaded and have already tried the steps listed on the xbox support website. Is there actually a way I can simply reinstall the game without having to download the whole 32GB?