roslaunch ca_gazebo create_2.launch error

edit

I'm trying to launch a gazebo simulation with this code but run into an error at this step:

• https://github.com/frankjoshua/create...
• roslaunch ca_gazebo create_2.launch
• [create_2.launch] is neither a launch file in package [ca_gazebo] nor is [ca_gazebo] a launch file name

Console:

Workspace configuration appears valid.
[build] Found '5' packages in 0.0 seconds.                                     
[build] Package table is up to date.                                           
Starting  >>> ca_description                                                   
Finished  <<< ca_description                [ 0.3 seconds ]                    
Starting  >>> ca_msgs                                                          
Finished  <<< ca_msgs                       [ 0.9 seconds ]                    
Starting  >>> ca_tools                                                         
Finished  <<< ca_tools                      [ 0.2 seconds ]                    
Starting  >>> ca_driver                                                        
Finished  <<< ca_driver                     [ 1.9 seconds ]                    
[build] Summary: All 4 packages succeeded!                                     
[build]   Ignored:   1 packages were skipped or are blacklisted.               
[build]   Warnings:  None.                                                     
[build]   Abandoned: None.                                                     
[build]   Failed:    None.                                                     
[build] Runtime: 3.5 seconds total.                                            

hannah@hannah-VirtualBox:~/create_ws$ source ~/create_ws/devel/setup.bash

hannah@hannah-VirtualBox:~/create_ws$ roslaunch ca_gazebo create_2.launch

[create_2.launch] is neither a launch file in package [ca_gazebo] nor is [ca_gazebo] a launch file name
The traceback for the exception was written to the log file

hannah@hannah-VirtualBox:~/create_ws$ source devel/setup.bash

hannah@hannah-VirtualBox:~/create_ws$ cd

hannah@hannah-VirtualBox:~$ source devel/setup.bash

bash: devel/setup.bash: No such file or directory

hannah@hannah-VirtualBox:~$ roslaunch ca_gazebo create_2.launch

[create_2.launch] is neither a launch file in package [ca_gazebo] nor is [ca_gazebo] a launch file name
The traceback for the exception was written to the log file