This package is part of the ROS-Industrial program.
To view and manipulate the arm models in rviz, install the package from package management and launch the following:
roslaunch ur_description ur5_upload.launch roslaunch ur_description test.launch
You should see an rviz window showing the UR5 in a lying-down position, and a separate window where the joint values may be manually specified. Note that this is not a simulation, just a visualization of the arm model. To simulate UR5 or UR10, see ur_gazebo.