cant find header files ROS open with QT Creator

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I have ubuntu 18.04 + ROS melodic

I am following the ros tutorials for begginers

I have roscpp added to my include compoents in cmakelists

I am trying to open a cpp file in my project in the final src folder in my catkin workspace, as the tutorial does.

Tried opening cpp file. and it cannot find header files.

Error that come up in creator:

warning: this file is not part of any project
General messages: [ROS Warning] Unable to locate build directory for package: beginner_tutorials.
[ROS Warning] Failed to source workspace because this file does not exist: setup.bash.

in opening the cpp file in qt:

file, open new file->other project-> rosworkspace -> pjct name: catkin_ws buildsystem:CtakinTools choose workspace path=: /catkin_ws

i open workspace which is fine:

warning: [ROS Warning] Unable to locate package beginner_tutorials build file: /home/joe/catkin_ws/build/beginner_tutorials/beginner_tutorials.cbp.
[ROS Debug] Sourced workspace: /home/joe/catkin_ws/devel/setup.bash.