Implementing Deferred Deep Linking in iOS App

Question

Question:

I have an existing iOS app, and I want to implement deferred deep linking. The goal is to provide a URL or link to customers that, when clicked, should:

1. Direct users to the app if it's already installed.
2. Open the App Store to download the app if it's not installed.

I'm not sure how to achieve this. How can one URL handle both cases (app installed and not installed)? Could someone provide a general way of achieving this?

I have seen tutorials and read the Apple doc, but haven't understood the general way of achieving this. Any leads would be appreciated.

Thanks!