Doc>Python scripting: Add instructions to install the Python package ('wheel')

hugo/content/py/_index.md

@@ -25,5 +25,16 @@ one can
 {{< figscg src="nodes_pycharm_ide.png" width="500" class="center"
     caption="A BornAgain script running in the PyCharm IDE.">}}
 
+
+## Installing the Python package
+The installer for any supported platform includes, among others, a Python package ('wheel');
+for instance, for Python 3.9, the package can be found under `python/3.9/wheel` folder.
+
+The package can be installed via the standard Python's `pip`; e.g.,
+```
+python3 -m pip install <BornAgain-wheel-file>
+```
+For further options, consult [pip's documentation](https://pip.pypa.io/en/stable).
+
 Read on:
 {{% children %}}