What are the pre-requisits (such AR Foundation / AR Core XR plugin) that I should install and begin with?
Thanks for you question! I assume you have read the blog already.
Google provides guides for setting up AR Core on Android, iOS, in Unity and UE:
If you want to use Unity, as described in the blog, you can download and install AR Core SDK for Unity.
However, things got changed since the blog was released and updated, and now Google recommends using Unity AR Foundation instead..