How to tap into inbound customer calls to view incoming calls on a cutom built React UI

Hi, I am trying to fetch inbound calls to my custom-built UI but am not able to find much information in terms of what notifications or API calls I should look for. Can someone help in this regard?
All I want is to receive inbound customer calls to React UI. The dataflow would be something like, from Genesys cloud to third-party UI app.