Clarification for #298

Author: pgleeson

README.md

@@ -45,12 +45,13 @@ in addition for Linux instructions.
 
 **Running**
 
-1. Open a terminal and run: `git clone http://github.com/openworm/openworm`; `cd openworm`
-2. Optional: Run `./build.sh` (or `build.cmd` on Windows). If you skip this step, it will download the latest released Docker image from the [OpenWorm Docker hub](https://hub.docker.com/r/openworm/openworm). 
-3. Run `./run.sh` (or `run.cmd` on Windows).
-4. About 5-10 minutes of output will display on the screen as the steps run.
-5. The simulation will end.  Run `stop.sh` (`stop.cmd` on Windows) on your system to clean up the running container.
-6. Inspect the output in the `output` directory on your local machine.
+1. Ensure the Docker daemon is running in the background (on MacOS/Windows there should be an icon with the Docker whale logo showing in the menu bar/system tray). 
+2. Open a terminal and run: `git clone http://github.com/openworm/openworm`; `cd openworm`
+3. Optional: Run `./build.sh` (or `build.cmd` on Windows). If you skip this step, it will download the latest released Docker image from the [OpenWorm Docker hub](https://hub.docker.com/r/openworm/openworm). 
+4. Run `./run.sh` (or `run.cmd` on Windows).
+5. About 5-10 minutes of output will display on the screen as the steps run.
+6. The simulation will end.  Run `stop.sh` (`stop.cmd` on Windows) on your system to clean up the running container.
+7. Inspect the output in the `output` directory on your local machine.
 
 **Advanced**