I can't modify variables

[anyhelpworks]

Hi.
I am new to programming and robotics. I started doing a tutorial available here : https://zenn.dev/tasada038/articles/416c8ffe7e964e

I completed it till the end without having much issue.
However, when I tried to modify the turtlebot's velocity, I am facing issues.
Even though I edit the linear velocity linear_x in "move_robot_action.hpp" and "detect_camera_action.hpp", there is no change in the simulation. I changed the message_linear.x values to 0.0 and 0.5 in tick for "move_robot_action.hpp" to check. I also edited line 107 in "detect_camera_action.hpp". But no change in the simulation.

I have done colcon build after editing these files. I have also done ". install/setup.bash" to see if it helps, but it didn't.
I also edited the linear_x values in groot to 0, but nothing is helping me.

Could anyone give me any further instructions for changing the veloctiy and movement?