The initial details that the App component needs

initial-app-details.js

const APP_ID = process.env.REACT_APP_APP_ID;
const USER_ID = process.env.REACT_APP_USER_ID;
const NICKNAME = process.env.REACT_APP_NICKNAME;
const ACCESS_TOKEN = process.env.REACT_APP_ACCESS_TOKEN;
 
function App() {
   return (
       <div className="App">
           <SendbirdApp
               appId={APP_ID}   // Specify your Sendbird application ID.
               userId={USER_ID}        // Specify your user ID.
               nickname={NICKNAME}   //Specify nickname
               accessToken={ACCESS_TOKEN} //If access token is generated in dashboard, it must be passed in here
           />
       </div>
   );
};
 
export default App;