This practical depends on the resources that were downloaded in previous practicals. Modify amcl_demo.launch as follows
cd robotics/src/rosbot_description/src/rosbot_navigation/launch
code amcl_demo.launch
replace the section under <!---Movebase---> with the following section
<!-- Move base -->
<node pkg="move_base" type="move_base" respawn="false" name="move_base" output="screen">
<rosparam file="$(find rosbot_navigation)/config/costmap_common_params.yaml" command="load" ns="global_costmap" />
<rosparam file="$(find rosbot_navigation)/config/costmap_common_params.yaml" command="load" ns="local_costmap" />
<rosparam file="$(find rosbot_navigation)/config/local_costmap_params.yaml" command="load" />
<rosparam file="$(find rosbot_navigation)/config/global_costmap_params.yaml" command="load" />
<rosparam file="$(find rosbot_navigation)/config/teb_local_planner.yaml" command="load" />
<rosparam file="$(find rosbot_navigation)/config/global_planner_params.yaml" command="load" />
<rosparam file="$(find rosbot_navigation)/config/move_base_params.yaml" command="load" />
<remap from="cmd_vel" to="cmd_vel"/>
<remap from="odom" to="odom"/>
<remap from="scan" to="/scan"/>
<param name="move_base/DWAPlannerROS/yaw_goal_tolerance" value="1.0"/>
<param name="move_base/DWAPlannerROS/xy_goal_tolerance" value="1.0"/>
</node>