The ROS Wiki is for ROS 1. Are you using ROS 2 (Humble, Iron, or Rolling)? Check out the ROS 2 Project DocumentationPackage specific documentation can be found on index.ros.org
For tutorials, check out the pr2 mechanism tutorial page
Wiki: pr2_mechanism_msgs/Tutorials (last edited 2009-11-20 20:57:15 by wim)