Help fix flutter deep linking -- 2

We have a flutter app published in app stores. We are working on a new feature to introduce deep links to allow users to reach a screen directly using a link. We have successfully managed to configure most of it except while testing the app doesn't open rather it leads to chrome. Also we need to implement the check if app isn't installed redirect to download page.

We are looking for someone to guide us who has already implemented deep linking before. We aren't using firebase or branch.io.