Open world map on low end pc

I’m working on a open FPS game similar to something like Far Cry. I’ve created the gameplay mechanics and the AI’s. Now I’m on my way to start working on the open world and the story of game(haven’t thought it yet) but I’m having a low end pc, specs:
Ryzen 3 2200G
12gb ddr4 ram
GT 1030 2gb GPU.
Now my question is how do I make a open world map on this hardware? Also if you have any game stories for some sort of open world adventure game, please do share it with me coz I haven’t thought any story yet.
Please answer,

Check out World Composition: World Composition User Guide | Unreal Engine Documentation

It allows you to split your world up into smaller levels so you don’t have to have them all loaded at once.