I know that repository. My problem was that i dont understand what to do after creating a workspace. I didnt create anything in catkin_ws but I tried to do http://wiki.ros.org/catkin/Tutorials/... tutorial with that darmstadt repository. do you think this would solve my problem?

The repository provides already made packages. You just have to copy the ones you want in your catkin workspace.

But first of all, I recommend you to learn all beginner tutorials. It is the minimum required in order to use ROS correctly (and to have a better understanding).

As i said before my problem is that i found some of the tutorials (even the beginner tutorials) confusing. So while reading and applying tutorials i am asking some help in here.

Yes I understood. I am just trying to tell you how to modify the hector_slam package. It is well what you want, no ?

To answer your question again, you have to copy the packages you want of the repository (as indicated in the tutorial) in the workspace you have created (in the workspace/src). Then you can modify the sources as you prefer. I hope it helps you.

yes, i wanna modify them :) sorry but which tutorial are you talking about?

The one which speaks about the git clone.

can you give the link of the tutorial please?