Kinematic rosject can not launch teleop

roslaunch turtlebot3_teleop turtlebot3_teleop_key.launch... logging to /home/user/.ros/log/918b7f18-ace2-11ec-a61e-0242ac140007/roslaunch-1_xterm-15422.log
Checking log directory for disk usage. This may take a while.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

RLException: Invalid <arg> tag: environment variable 'TURTLEBOT3_MODEL' is not set.

Arg xml is <arg name="model" default="$(env TURTLEBOT3_MODEL)" doc="model type [burger, waffle, waffle_pi]"/>
The traceback for the exception was written to the log fil


Duplicate question:Basic Kinematics of Mobile Robots rosject can not launch teleop