diff --git a/README.md b/README.md
index 01c1bd1..cde91d6 100644
--- a/README.md
+++ b/README.md
@@ -41,6 +41,23 @@ $ gpg-group-chat --server
 $ gpg-group-chat --client
 ```
 
+## Basic usage flow
+
+1. Server starts with gpg-group-chat --server at 192.168.0.1
+2. The client1 starts with gpg-group-chat --client --server-ip=192.168.0.1 --public-key=public-key1
+3. The client1 connect to the server and the it stores the public key for client1
+4. The server send the current list of keys for client1 (contains public key1)
+5. The client2 starts with gpg-group-chat --client --server-ip=192.168.0.1 --public-key=public-key2
+6. The client2 connect to the server and the it stores the public key for client2
+7. The server send the current list of keys for client1 and client2 (contains public key1 and public key2)
+8. The client3 starts with gpg-group-chat --client --server-ip=192.168.0.1 --public-key=public-key3
+9. The client3 connect to the server and the it stores the public key for client3
+10. The server send the current list of keys for client1, client2 and client3 (contains public key1, public key2 and public key3)
+11. The client2 disconnects from the server
+12. the server delete the public key from client 2 from the storage
+13. The server send the current list of keys for client1 and client3 (contains public key1 and public key3)
+...
+
 # Issue board
 
 [Waffle.io/bahackers/gpg-group-chat](https://waffle.io/bahackers/gpg-group-chat)
diff --git a/gpg_group_chat/client/client.py b/gpg_group_chat/client/client.py
index f8867fd..4ecf3b1 100644
--- a/gpg_group_chat/client/client.py
+++ b/gpg_group_chat/client/client.py
@@ -1,4 +1,54 @@
+import select
+import socket
+import sys
+
+
 class Client():
 
-    def start(self, port, host):
-        print('Hello friend!')
+    def __init__(self):
+        self._socket = None
+        self._working = True
+
+    def start(self, server_port, server_ip):
+        print('Hello friend')
+        dest = (server_ip, server_port)
+
+        try:
+            self._socket = socket.create_connection(dest)
+        except ConnectionRefusedError as err:
+            print('Connection refused')
+            sys.exit(1)
+
+        self._handle_messages()
+
+    def _handle_messages(self):
+        input_list = [sys.stdin, self._socket]
+        self._prompt()
+        while self._working:
+            ready_to_read, _, _ = select.select(input_list, [], [])
+            self._handle_input_channel(ready_to_read)
+
+    def _handle_input_channel(self, ready_to_read):
+        for input_channel in ready_to_read:
+            if input_channel is self._socket:
+                self._receive_data_from_server()
+            else:
+                self._send_message_to_server()
+
+    def _receive_data_from_server(self):
+        data = self._socket.recv(4096)
+        if not data:
+            print('\nDisconnected from chat server')
+            sys.exit(0)
+        else:
+            print(data.decode('utf-8'))
+            self._prompt()
+
+    def _send_message_to_server(self):
+        msg = '[*] %s' % input()
+        self._socket.send(msg.encode('utf-8'))
+        self._prompt()
+
+    def _prompt(self):
+        print('[Me] ', end='')
+        sys.stdout.flush()
diff --git a/gpg_group_chat/server/server.py b/gpg_group_chat/server/server.py
index c1c861e..abc8c72 100644
--- a/gpg_group_chat/server/server.py
+++ b/gpg_group_chat/server/server.py
@@ -10,7 +10,7 @@ def __init__(self):
         self._working = False
 
     def start(self, port, target):
-        print('Server listening on %s:%d' % (target, port))
+        print('Server is not done yet!')
         self._working = True
         try:
             self._socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
@@ -49,3 +49,4 @@ def _client_handler(client_socket, thread_event):
                 break
             else:
                 print('[INFO] Received: %s' % data)
+                client_socket.sendall(b'\rACK{}\n')
diff --git a/gpg_group_chat/utils.py b/gpg_group_chat/utils.py
new file mode 100644
index 0000000..7da6e4a
--- /dev/null
+++ b/gpg_group_chat/utils.py
@@ -0,0 +1,2 @@
+def show_help():
+    print('Helper will be available soon!')
diff --git a/test/client/client_test.py b/test/client/client_test.py
index 5571151..820f181 100644
--- a/test/client/client_test.py
+++ b/test/client/client_test.py
@@ -1,5 +1,88 @@
-import gpg_group_chat.client
+from gpg_group_chat.client.client import Client
+from socket import socket as SocketType
+from unittest import TestCase
+from unittest.mock import Mock
+from unittest.mock import patch
+import sys
 
 
-def test_start_gpg_groupd_chat():
-    assert True
+class ClientTest(TestCase):
+
+    def setUp(self):
+        self.create_connection = patch('socket.create_connection').start()
+        self.exit = patch('sys.exit').start()
+        self.readline = patch('sys.stdin.readline').start()
+        self.select = patch('select.select').start()
+        self.print_stdout = patch('sys.stdout.write').start()
+
+        self.socket = Mock(SocketType)
+        self.create_connection.return_value = self.socket
+
+        self.client = Client()
+
+    def test_connect_to_a_server(self):
+        def _handle_messages():
+            pass
+
+        self.client._handle_messages = _handle_messages
+        self.client.start(9999, '127.0.0.1')
+
+        self.create_connection.assert_called_once_with(('127.0.0.1', 9999))
+
+    def test_to_connect_to_unexist_server(self):
+        def side_effect(dest):
+            raise ConnectionRefusedError(111, 'connection refused')
+
+        def _handle_messages():
+            pass
+
+        self.create_connection.side_effect = side_effect
+        self.client._handle_messages = _handle_messages
+
+        self.client.start(9999, 'server.runkown')
+
+        self.exit.assert_called_once_with(1)
+
+    def test_send_a_message_to_the_server(self):
+        def side_effect(msg):
+            self.client._working = False
+
+        self.socket.send.side_effect = side_effect
+        self.readline.return_value = 'message'
+        self.select.return_value = ([sys.stdin], None, None)
+
+        self.client.start(9999, '127.0.0.1')
+
+        self.socket.send.assert_called_once_with(b'[*] message')
+
+    def test_receive_a_message_from_the_server(self):
+        def side_effect(size):
+            self.client._working = False
+            return b'message from server'
+
+        self.socket.recv.side_effect = side_effect
+        self.select.return_value = ([self.socket], None, None)
+
+        self.client.start(9999, '127.0.0.1')
+
+        self.print_stdout.assert_any_call('message from server')
+
+    def test_exit_when_disconnect_with_the_server(self):
+        def side_effect(size):
+            self.client._working = False
+            return None
+
+        self.socket.recv.side_effect = side_effect
+        self.select.return_value = ([self.socket], None, None)
+
+        self.client.start(9999, '127.0.0.1')
+
+        self.print_stdout.assert_any_call('\nDisconnected from chat server')
+        self.exit.assert_called_once_with(0)
+
+    def test_the_prompt_meyhod_does_not_print_with_break_line_char(self):
+        def side_effect(txt):
+            assert not txt.endswith('\n')
+
+        self.print_stdout.side_effect = side_effect
+        self.client._prompt()