Where to put files for ros
I'm new to ROS(an not too confident in my skills with the file system in linux) and am trying to make a basic robot to simulate on Gazebo. I understand that one of the things I need to do is create the robot chassis from a urdf file, along with the nodes to control it etc... But I'm not entirely sure where to to put these files. Not just files I would make but packages I would have downloaded where would I extract them to. Would they go in the workspace directory that tutorials had me make in my home directory? Or would they have to go in the gazebo directory which is in the ROS directory which is in the opt directory? Or does it even matter?
Thanks.