doc: add note about setting core device IP

doc/manual/getting_started.rst

@@ -23,7 +23,7 @@ As a very first step, we will turn on a LED on the core device. Create a file ``
 
 The central part of our code is our ``LED`` class, that derives from :class:`artiq.language.environment.EnvExperiment`. Among other features, ``EnvExperiment`` calls our ``build`` method and provides the ``attr_device`` method that interfaces to the device database to create the appropriate device drivers and make those drivers accessible as ``self.core`` and ``self.led``. The ``@kernel`` decorator tells the system that the ``run`` method must be executed on the core device (instead of the host). The decorator uses ``self.core`` internally, which is why we request the core device using ``attr_device`` like any other.
 
-Copy the files ``ddb.pyon`` and ``pdb.pyon`` (containing the device and parameter databases) from the ``examples`` folder of ARTIQ into the same directory as ``led.py`` (alternatively, you can use the ``-d`` and ``-p`` options of ``artiq_run.py``). You can open the database files using a text editor - their contents are in a human-readable format.
+Copy the files ``ddb.pyon`` and ``pdb.pyon`` (containing the device and parameter databases) from the ``examples`` folder of ARTIQ into the same directory as ``led.py`` (alternatively, you can use the ``-d`` and ``-p`` options of ``artiq_run.py``). You can open the database files using a text editor - their contents are in a human-readable format. You will probably want to set the IP address of the core device in ``ddb.pyon`` so that the computer can connect to it (it is the ``host`` parameter of the ``comm`` entry).
 
 Run your code using ``artiq_run``, which is part of the ARTIQ front-end tools: ::