add Msg Components in ChatScreen.js

 import React from "react";
 import styled from "styled-components";
-import ChatListBox from "../SubMenuList/ChatListBox";
+import IncomingMsg from "./IncomingMsg";
+import OutcomingMsg from "./OutcomingMsg";
 
 const ChatScreen = styled.div``;
 
 export default () => {
   return (
     <ChatScreen>
-      <ChatListBox />
+      <IncomingMsg />
+      <OutcomingMsg />
     </ChatScreen>
   );
 };