Add example launch script to documentation.

[skip ci]

README.md

@@ -30,9 +30,44 @@ pip install git+https://github.com/ethanluoyc/lxm3
 ```
 
 ## Documentation
-Since lxm3 implements the XManager API, you should get familiar with the concepts in the [XManager](https://github.com/deepmind/xmanager). Once you are familiar with the concepts, checkout the [examples/](examples/) directory for a quick start guide.
+At a high level you can launch experiment by creating a launch script
+called `launcher.py` that looks like:
+
+```python
+with xm_cluster.create_experiment(experiment_title="hello world") as experiment:
+    # Launch on a Slurm cluster
+    executor = xm_cluster.Slurm()
+    # or, if you want to use SGE:
+    # executor = xm_cluster.GridEngine()
+    # or, if you want to run locally:
+    # executor = xm_cluster.Local()
+
+    spec = xm_cluster.PythonPackage(
+       path=".",
+       entrypoint=xm_cluster.ModuleName("my_package.main"),
+    )
+
+    # package your code
+    [executable] = experiment.package(
+        [xm.Packageable(spec, executor_spec=executor.Spec())]
+    )
+
+    # add jobs to your experiment
+    experiment.add(
+        xm.Job(executable=executable, executor=executor)
+    )
+```
+and launch the experimet from the command line with
+```python
+lxm3 launch launcher.py
+```
+
+Many things happen under the hood. Since lxm3 implements the XManager
+API, you should get familiar with the concepts in the
+[XManager](https://github.com/deepmind/xmanager). Once you are
+familiar with the concepts, checkout the [examples/](examples/)
+directory for a quick start guide.
 
-TODO: Add a simple example for usage.
 
 ## Components
 lxm3 provides the following executable specification and executors.

docs/index.rst

@@ -9,7 +9,41 @@ Welcome to LXM3's documentation!
 LXM3 provides an implementation for DeepMind's
 `XManager <https://github.com/deepmind/xmanager/tree/main>`_ launch API
 that aims to provide a similar experience for running experiments on
-traditional HPC.
+traditional HPC (SGE, Slurm).
+
+With LXM3, launching your job on a HPC cluster is as simple as
+creating a launch script, e.g. ``launcher.py``:
+
+.. code-block:: python
+
+   with xm_cluster.create_experiment(experiment_title="Hello World") as experiment:
+      executor = xm_cluster.Slurm()
+      # or, if you want to use SGE:
+      # executor = xm_cluster.GridEngine()
+      # or, if you want to run locally:
+      # executor = xm_cluster.Local()
+
+      spec = xm_cluster.PythonPackage(
+         path=".",
+         entrypoint=xm_cluster.ModuleName("my_package.main"),
+      )
+
+      # package your code
+      [executable] = experiment.package(
+          [xm.Packageable(spec, executor_spec=executor.Spec())]
+      )
+
+      # add jobs to your experiment
+      experiment.add(
+          xm.Job(executable=executable, executor=executor)
+      )
+
+
+and run the command
+
+.. code-block::
+
+   lxm3 launch launcher.py
 
 .. toctree::
    :maxdepth: 2