Cant find app on chromebook

I have an app which i use on my phone and want to use on my chromebook but when i try to install it it says already installed yet i can not find it on the Chromebook. On my google account under devices, the chromebook is not listed but i have no idea how to add it?? Any help would be greatly appreciated.

Welcome to Android Central! Which Chromebook? Are you sure your Chromebook supports Android apps? If so, are you sure you're using the Play Store app that should present in your app dock at the bottom of the screen, rather than the Play Store website?