[DOCS] A draft of Installation page

docs/source/user/installation.rst

@@ -1,2 +1,73 @@
 Installation
 ============
+
+Preface
+-------
+
+As was mentioned [#f1]_, you need two pieces of software to use
+the platform:
+
+- the platform itself;
+- and some client application.
+
+This tutorial is mostly related to the platform itself. For details
+about the installation and usage of client applications, please
+visit the :doc:`./client_applications` page.
+
+
+System Requirements
+-------------------
+
+Minimum System Requirements:
+
+- Python 3.5 [#f2]_
+- bash
+
+Recommended System Requirements:
+
+- Python 3.5 or newer
+- UNIX-like operating system (like macOS and Linux-based systems)
+- hardware support of protocols like Bluetooth, ZigBee and so on
+  for different :doc:`./integrations`
+
+
+Manual Installation Steps
+-------------------------
+
+1. Download an archive with the latest stable release of platform
+   from its repository: https://github.com/s-kostyuk/adpl/releases
+
+.. NOTE::
+    You can also download the latest development (unstable) version
+    here: https://github.com/s-kostyuk/adpl by clicking a 'clone or
+    download' button.
+
+2. Extract archive content to some directory. Remember its
+   placement (path).
+
+3. Open terminal emulator, switch to the platform's directory::
+
+    cd /path/to/platforms/directory
+
+4. Install all needed dependencies that are listed in
+   ``requirements.txt`` [#f3]_ file. The most simple way to do this
+   is to use pip::
+
+    pip3 install -r requirements.txt
+
+5. Now it's possible to run the main execution file::
+
+    bash ./dpl/run.sh
+
+Installation finished!
+
+.. rubric:: Footnotes
+
+.. [#f1] Documentation page: :doc:`./getting_started`
+.. [#f2] async/await expressions which are commonly used
+        in the platform was introduced only in Python 3.5.
+
+        In a case if you need a support of older versions of python -
+        please, endorse this issue: `#22 <https://github.com/s-kostyuk/adpl/issues/22>`_.
+.. [#f3] Requirements file is placed in the root of platform's directory,
+         for example: https://github.com/s-kostyuk/adpl/blob/devel/requirements.txt