Updating Notes

README.md

@@ -2,6 +2,12 @@
 
 ## Start up
 From the ~/workspace/ros directory
+
+Build if you have not already
+```
+catkin_make
+```
+
 ```
 roscore
 ```
@@ -209,4 +215,4 @@ rosrun rqt_plot rqt_plot
 ```
 
 
-[Understanding ROS Parameters and Services](https://wiki.ros.org/ROS/Tutorials/UnderstandingServicesParams
+[Understanding ROS Parameters and Services](https://wiki.ros.org/ROS/Tutorials/UnderstandingServicesParams