How to have seamless boundary for my landscape ?

Hi Everyone,

I am pretty new to UE. I am playing with landscapes and volumes.
In order to dive into UE I started a project that has island and surrounded by ocean.

My Aim is to have seamless view of ocean but I don’t know how to achieve that. Basically the ocean should expand to horizon ( to Sphere). I checked Community ocean project but I want to how they achieved it.

Once I have that I am planning to set invisible boundaries to limit player going beyond that point.

Can any one show me the path to achieve this ?