diff --git a/docs/backup-protocol.rst b/docs/backup-protocol.rst
index ec594c7c..27adcb1d 100644
--- a/docs/backup-protocol.rst
+++ b/docs/backup-protocol.rst
@@ -19,10 +19,77 @@ be upgraded to a HTTP/2 connection using
   UPGRADE: proxmox-backup-protocol-v1
 
 The server replies with HTTP 101 Switching Protocol status code,
-and you can then issue REST command on that updated HTTP/2 connection.
+and you can then issue REST commands on that updated HTTP/2 connection.
 
-Please use the `API Viewer <api-viewer/index.html>`_ for details about
-available REST commands.
+The backup protocol allows you to upload three different kind of files:
+
+- Chunks and blobs (binary data)
+
+- Fixed Indexes (List of chunks with fixed size)
+
+- Dynamic Indexes (List of chunk with variable size)
+
+The following section gives a short introduction how to upload such
+files. Please use the `API Viewer <api-viewer/index.html>`_ for
+details about available REST commands.
+
+
+Upload Blobs
+~~~~~~~~~~~~
+
+Uploading blobs is done using ``POST /blob``. The HTTP body contains the
+data encoded as ``DataBlob`` (see source code).
+
+The file name needs to end with ``.blob``, and is automatically added
+to the backup manifest.
+
+
+Upload Chunks
+~~~~~~~~~~~~~
+
+Chunks belong to an index, so you first need to open an index (see
+below). After that, you can upload chunks using ``POST /fixed_chunk``
+and ``POST /dynamic_chunk``. The HTTP body contains the chunk data
+encoded as ``DataBlob`` (see source code).
+
+
+Upload Fixed Indexes
+~~~~~~~~~~~~~~~~~~~~
+
+Fixed indexes are use to store VM image data. The VM image is split
+into equally sized chunks, which are uploaded individually. The index
+file simply contains a list to chunk digests.
+
+You create a fixed index with ``POST /fixed_index``. Then upload
+chunks with ``POST /fixed_chunk``, and append them to the index with
+``PUT /fixed_index``. When finished, you need to close the index using
+``POST /fixed_close``.
+
+The file name needs to end with ``.fidx``, and is automatically added
+to the backup manifest.
+
+
+Upload Dynamic Indexes
+~~~~~~~~~~~~~~~~~~~~~~
+
+Dynamic indexes are use to store file archive data. The archive data
+is split into dynamically sized chunks, which are uploaded
+individually. The index file simply contains a list to chunk digests
+and offsets.
+
+You create a dynamic sized index with ``POST /dynamic_index``. Then
+upload chunks with ``POST /dynamic_chunk``, and append them to the index with
+``PUT /dynamic_index``. When finished, you need to close the index using
+``POST /dynamic_close``.
+
+The file name needs to end with ``.didx``, and is automatically added
+to the backup manifest.
+
+Finish Backup
+~~~~~~~~~~~~~
+
+Once you have uploaded all data, you need to call ``POST
+/finish``. This commits all data and ends the backup protocol.
 
 
 Restore/Reader Protocol API
@@ -36,7 +103,38 @@ be upgraded to a HTTP/2 connection using
   UPGRADE: proxmox-backup-reader-protocol-v1
 
 The server replies with HTTP 101 Switching Protocol status code,
-and you can then issue REST command on that updated HTTP/2 connection.
+and you can then issue REST commands on that updated HTTP/2 connection.
 
-Please use the `API Viewer <api-viewer/index.html>`_ for details about
+The reader protocol allows you to download three different kind of files:
+
+- Chunks and blobs (binary data)
+
+- Fixed Indexes (List of chunks with fixed size)
+
+- Dynamic Indexes (List of chunk with variable size)
+
+The following section gives a short introduction how to download such
+files. Please use the `API Viewer <api-viewer/index.html>`_ for details about
 available REST commands.
+
+
+Download Blobs
+~~~~~~~~~~~~~~
+
+Downloading blobs is done using ``GET /download``. The HTTP body contains the
+data encoded as ``DataBlob`` (see source code).
+
+
+Download Chunks
+~~~~~~~~~~~~~~~
+
+Downloading chunks is done using ``GET /chunk``. The HTTP body contains the
+data encoded as ``DataBlob`` (see source code).
+
+
+Download Index Files
+~~~~~~~~~~~~~~~~~~~~
+
+Downloading index files is done using ``GET /download``. The HTTP body
+contains the data encoded as ``FixedIndex`` or ``DynamicIndex`` (see
+source code).