1. To start using the Hokuyo URG-04LX-UG01, we have to install the drivers.
2. Download the package from the repository and build the package from the source since ROS distribution does not contain the pre-built binary package:

$ cd ~/catkin_ws/src
$ git clone git clone https://github.com/ros-drivers/driver_common.git
$ git clone https://github.com/ros-drivers/hokuyo_node.git
$ cd ..
$ catkin_make