improve poetry usage documentation (rytilahti#830)

* improve poetry usage documentation

* cleanup

docs/new_devices.rst

@@ -10,11 +10,17 @@ Development environment
 -----------------------
 
 This section will shortly go through how to get you started with a working development environment.
-We use `poetry <https://python-poetry.org/>`__ for managing the dependencies and packaging, so simply execute:
+We use `poetry <https://python-poetry.org/>`__ for managing the dependencies and packaging, so simply execute::
 
     poetry install
 
-To verify the installation, simply launch tox_ to run all the checks::
+If you were not already inside a virtual environment during the install,
+poetry will create one for you.
+You can execute commands inside this environment by using ``poetry run <command>``,
+or alternatively,
+enter the virtual environment shell by executing ``poetry shell`` to avoid repeating ``poetry run``.
+
+To verify the installation, you can launch tox_ to run all the checks::
 
     tox