community-chat-platform: Rewrite section

Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>

community-chat-platform.rst

@@ -2,31 +2,47 @@
 ..
 .. SPDX-License-Identifier: CC-BY-4.0
 
-.. include:: ./definitions.rst
-
 Community Chat Platform
 #######################
 
-`GitLab Mattermost <https://mattermost.com/>`__ is used as the primary
-communication tool by project members, contributors, and the community.
+.. contents::
+      :depth: 2
+
+Overview
+********
+
+OpenHarmony has a friendly community providing an open platform for
+discussions. `The OSTC Mattermost instance <https://chat.ostc-eu.org>`_ is used
+as the primary communication tool by project members, contributors, and the
+community.
+
+Authentication
+**************
+
+To access the `OSTC Mattermost instance <https://chat.ostc-eu.org>`_, one will
+need an account on the project's GitLab instance. The chat platform will handle
+the authentication through GitLab, redirecting the user accordingly. New
+account registration can be handled through this authentication process as well
+by using the ``Register now`` link in GitLab.
 
-For any communication about |main_project_name|, user can sign up using GitLab
-credentials and join the community chat at mattermost using the URL
-https://chat.ostc-eu.org/.
+* Go to `<https://chat.ostc-eu.org>`
+* Login request will redirect you to `<https://git.ostc-eu.org>`
+  * Login using an existing account
+  * Create a new account following ``Register now`` link
+* The system will redirect you back to `<https://chat.ostc-eu.org>`
 
-If you encounter any problems when using |main_project_name|, join `town-square <https://chat.ostc-eu.org/ostc/channels/town-square>`__
-group for discussion.
+Chat Channels
+*************
 
-Bug reports and issues can be raised and tracked in
-https://git.ostc-eu.org/OSTC/OHOS/meta-ohos/-/issues.
+The `OSTC Mattermost instance <https://chat.ostc-eu.org>`_ is organised in
+channels. The main one is the `Town Square <https://chat.ostc-eu.org/ostc/channels/town-square>`_
+and provides a default place for communication.
 
-How Do I Subscribe to Mattermost?
-*********************************
-To join a Public channel, perform the following steps:
+To join/explore other a public channel, do the following:
 
 #. Select the **+** symbol at the top of the sidebar.
-#. Select Browse Channels and search through the list of Public channels.
-#. Select Join to join the communication channel.
+#. Select **Browse Channels** and search through the list of Public channels.
+#. Select **Join** to join a specific communication channel.
 
-For more details on Mattermost subscription, see
-https://docs.mattermost.com/guides/user.html.
+For more details on using our chat platform powered by Mattermost, check out the
+`Mattermost User’s Guide <https://docs.mattermost.com/guides/user.html>`_.