Add episode recording and playback guide (#14)

* Add episode recording and playback guide

* note -> tip

docs/operation.rst

@@ -7,3 +7,4 @@ Operation
 
   ./operation/mobile.rst
   ./operation/stationary.rst
+  ./operation/data_collection.rst

docs/operation/data_collection.rst

@@ -0,0 +1,92 @@
+===============
+Data Collection
+===============
+
+Task Creation
+=============
+
+Task configuration can be found in the ALOHA package's aloha module under ``constants.py`` in the ``TASK_CONFIGS`` dictionary.
+A template task (``aloha_template``) is provided containing all possible fields and some placeholder values.
+Here, we will focus only on the task name, the dataset directory, the episode length, and the observation cameras.
+
+.. list-table::
+  :align: center
+  :widths: 25 75
+  :header-rows: 1
+  :width: 60%
+
+  * - Configuration Field
+    - Description
+  * - Task Name
+    - The task name should accurately describe the task that the ALOHA is performing.
+  * - Dataset Directory
+    - The ``dataset_dir`` field sets the directory episodes will saved to.
+  * - Episode Length
+    - The ``episode_len`` field sets the length of the episode in number of timesteps.
+  * - Camera Names
+    - The ``camera_names`` field takes in a list of strings corresponding to camera names.
+      These camera names will be used as observation sources during dataset collection.
+
+Recording Episodes
+==================
+
+To record an episode, follow the steps below:
+
+#.  Bring up the ALOHA control stack according to your platform
+
+    * Stationary: :ref:`operation/stationary:Running ALOHA Bringup`
+    * Mobile: :ref:`operation/mobile:Running ALOHA Bringup`
+
+#.  Configure the environment and run the episode recording script as follows:
+
+  .. code-block:: bash
+
+    $ source /opt/ros/humble/setup.bash # configure ROS system install environment
+    $ source ~/interbotix_ws/install/setup.bash # configure ROS workspace environment
+    $ source /<path_to_aloha_venv>/bin/activate # configure ALOHA Python environment
+    $ cd ~/interbotix_ws/src/aloha/scripts/
+    $ python3 record_episodes.py --task_name <task_name> --episode_idx <episode_idx>
+
+  .. note::
+
+    The ``task_name`` argument should match one of the task names in the ``TASK_CONFIGS``, as configured in the :ref:`operation/data_collection:Task Creation` section.
+
+  .. tip::
+
+    Each platform has a "dummy" task that can be used to test basic data collection and playback.
+    For the Stationary variant, use the ``aloha_stationary_dummy`` task.
+    For the Mobile variant, use the ``aloha_mobile_dummy`` task.
+
+    An example for the Mobile variant would look like:
+
+    .. code-block:: bash
+
+      $ python3 record_episodes.py --task_name aloha_mobile_dummy --episode_idx 0
+
+Episode Playback
+================
+
+To play back a previously-recorded episode, follow the steps below:
+
+#.  Bring up the ALOHA control stack according to your platform
+
+    * Stationary: :ref:`operation/stationary:Running ALOHA Bringup`
+    * Mobile: :ref:`operation/mobile:Running ALOHA Bringup`
+
+#.  Configure the environment and run the episode playback script as follows:
+
+  .. code-block:: bash
+
+    $ source /opt/ros/humble/setup.bash # configure ROS system install environment
+    $ source ~/interbotix_ws/install/setup.bash # configure ROS workspace environment
+    $ source /<path_to_aloha_venv>/bin/activate # configure ALOHA Python environment
+    $ cd ~/interbotix_ws/src/aloha/scripts/
+    $ python3 replay_episodes.py --dataset_dir </path/to/dataset> --episode_idx <episode_idx>
+
+  .. tip::
+
+    An example for replaying the dummy Mobile episode recorded above would look like:
+
+    .. code-block:: bash
+
+      $ python3 replay_episodes.py --dataset_dir ~/aloha_data/aloha_mobile_dummy/ --episode_idx 0