doc: describe new TCF Settings page n TCM

doc/tooling/tcm/tcm_ui_overview.rst

@@ -357,14 +357,47 @@ TCF
 The **TCF** page provides an interface for clusters that run within `Tarantool Clusters Federation <https://www.tarantool.io/en/clustersfederation/>`__.
 
 .. image:: _images/tcm_ui_tcf.png
-    :align: left
+    :align: center
     :width: 700
     :alt: TCM TCF page
 
+TCF page can be added via the |tcm| configuration file:
+
+.. code-block:: yaml
+
+    # tcm.yaml
+    feature:
+        tcf:True
+
+
 On this page, you can:
 
--   view information about TCF clusters
--   switch cluster states in a TCF installation
+*   view information about TCF clusters
+*   toggle the state of clusters
+*   promote or demote clusters
+*   change key cluster parameters. To open the settings, click **Actions** (the three dots next to the cluster status) and select **Settings**. Available parameters:
+  - ``dml_users``: list of DML users
+  - ``cluster1``, ``cluster2``: cluster settings
+  - ``replication_user``: replication username
+  - ``replication_password``: password associated with the replication user
+  - ``failover_timeout``: time period (in seconds) to wait before initiating failover to another cluster. Default value: ``20``
+  - ``initial_status``: initial service state
+  - ``max_suspect_counts``: maximum suspect counts for failover. Default value: ``3``
+  - ``health_check_delay``: delay (in seconds) between health checks. Default value: ``2``
+  - ``enable_system_check``: enables or disables system-level health checks. Default value: ``true``
+  - ``status_ttl``: time-to-live for service status. Default value: ``4``
+
+
+    .. image:: _images/tcm_tcf_settings.png
+        :align: center
+        :width: 700
+        :alt: TCM TCF settings page
+
+    .. image:: _images/tcm_tcf_settings_params.png
+        :align: center
+        :width: 700
+        :alt: TCM TCF settings page
+
 
 Learn more in :ref:`tcm_cluster_tcf`.