Mbed Frimware installation

when I tried to run roslaunch rosbot_ekf all.launch command it is showing below error. It would be grateful if someone can help me with this.
husarion@husarion:~/ros_workspace$ roslaunch rosbot_ekf all.launch
[all.launch] is neither a launch file in package [rosbot_ekf] nor is [rosbot_ekf] a launch file name
The traceback for the exception was written to the log file

Please complete steps from this tutorial:

especially pay attention the step: