Add controller pairing guide

docs/getting_started/mobile.rst

@@ -7,3 +7,4 @@ Mobile ALOHA Getting Started
 
   ./mobile/hardware_setup.rst
   ./mobile/software_setup.rst
+  ./mobile/pairing_controller.rst

docs/getting_started/mobile/pairing_controller.rst

@@ -0,0 +1,46 @@
+=======================
+Pairing Your Controller
+=======================
+
+This guide walks you through setting up a Bluetooth joystick controller to control your ALOHA Mobile.
+
+#.  Open the **Settings** menu.
+
+#.  Open the **Bluetooth** settings menu.
+
+#.  Press and hold the **Share** button on the PS4 controller (see image below for reference).
+
+#.  While holding the **Share** button, press and hold the **PS Button**.
+    After a few seconds, the triangular shaped LED located between the **L2** and **R2** buttons should start rapidly flashing white (about twice a second) at which point you can let go.
+
+#.  Wait until you see **Wireless Controller** pop up in the Devices menu.
+    Select it, and click **Next** on the bottom right of the window.
+
+#.  A message should display saying **successfully set up new device 'Wireless Controller'** and the LED should turn blue.
+    This means the controller is connected to the computer.
+
+#.  To disconnect, hold down the **PS Button** for about 10 seconds until the LED turns off.
+
+.. image:: images/ps4.jpg
+    :width: 70%
+    :align: center
+
+.. note::
+
+    To reconnect, just press the **PS Button** (no need to hold it down).
+    After blinking white a few times, the LED should turn blue.
+
+Troubleshooting
+===============
+
+Controller Isn't Turning On
+---------------------------
+
+Your controller might be dead.
+Try charing it for an hour or plug it into your computer.
+
+PS4 Controller LEDs Blink A Few Times and Turn Off
+--------------------------------------------------
+
+Your controller may have a low charge level and needs to be charged.
+Try charing it for an hour or plug it into your computer.