Turtlebot3 bring up from PC doesn't work

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Hi, I am very new to this. I followed exactly(I believe) this http://turtlebot3.readthedocs.io/en/l... . I run roscore on my pc and launch on my turtlebot. When I tried to bring up rviz, by type in

export TURTLEBOT3_MODEL=burger
roslaunch turtlebot3_bringup turtlebot3_model.launch

I got this,

[turtlebot3_model.launch] is neither a launch file in package [turtlebot3_bringup] nor is [turtlebot3_bringup] a launch file name
The traceback for the exception was written to the log file

I checked all the package I had on pc, and there is indeed no turtlebot3_bringup. I am confused. I just expected it to work because I followed the tutorial closely.

How do I fix it? Maybe there is some small step I missed?