diff --git a/docs/index.rst b/docs/index.rst
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -4,13 +4,89 @@
 ===========================================
 
 This Python module provides a command line tool to replicate content objects from a
-source Object storage to a destination one by listening the `content` topic of a
-`swh.journal` kafka stream.
+source Object storage to a destination one by listening the ``content`` topic of a
+:ref:`swh-journal` kafka stream.
 
 It is meant to be used as the brick of a mirror setup dedicated to replicating content
 objects.
 
 
+Quick start
+-----------
+
+Once installed (using pip or debian packages), the command ``swh objstorage
+replay`` should be available:
+
+It needs a configuration file with 4 sections:
+
+- ``objstorage``: the source objstorage to retrieve objects from,
+
+- ``objstorage_dst``: the destination objstorage to put objects into,
+
+- ``journal_client``: the journal client (kafka configuration where the object
+  hashes are consumed from),
+
+- ``replayer`` (optional): some replayer specific configurations options.
+
+
+For example with a configuration file like:
+
+.. code-block:: yaml
+
+   objstorage:
+     cls: multiplexer
+     objstorages:
+       - cls: http
+         url: https://softwareheritage.s3.amazonaws.com/content/
+         compression: gzip
+       - cls: remote
+         url: https://login:password@objstorage.staging.swh.network
+
+   objstorage_dst:
+     cls: remote
+     args:
+       url: http://objstorage:5003
+
+   journal_client:
+     cls: kafka
+     brokers:
+     - broker1.journal.staging.swh.network:9093
+     group_id: kafka-username-content-replayer-003
+     sasl.username: kafka-username
+     sasl.password: kafka-password
+     security.protocol: sasl_ssl
+     sasl.mechanism: SCRAM-SHA-512
+     session.timeout.ms: 600000
+     max.poll.interval.ms: 3600000
+     message.max.bytes: 1000000000
+     privileged: true
+     batch_size: 2000
+
+   replayer:
+     error_reporter:
+       host: redis
+       port: 6379
+       db: 0
+
+
+you can start the content replayer with:
+
+.. code-block:: bash
+
+   $ swh objstorage -C replayer-config.yml replay
+
+
+You would typically run this tool on several machines, using the same
+``group_id``, to increase replication parallelism.
+
+Also note that you may increase the default concurrency within one replayer
+using the ``--concurrency`` command line option. This will use as many
+replication threads as given in argument, distributing the replication of
+objects **within the same kafka consumer** among these threads. This is
+typically useful when the replication of one object comes with non negligeable
+minimal latency (e.g. consuming from public cloud-based objstorages).
+
+
 Reference Documentation
 -----------------------