How to launch robot_localization nodes?

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GOAL

I want to use a node from this package (EKF node) with one of its possible inputs (IMU).

PROBLEM

Using this package: About this package: http://wiki.ros.org/robot_localization

I can't launch the node because of missing yaml code (?). The documentation mentions no yaml code, except for a totally different node I'm not touching. I also cannot find the source code of the node, to take a look inside. The documentation doesn't help in explaining how to specify a particular type of input, either.

p@t:/opt/ros/kinetic/share/robot_localization/launch$ ls -a
.  ..  dual_ekf_navsat_example.launch  ekf_template.launch  navsat_transform_template.launch  ukf_template.launch

there is no ekf node to launch, but there is a template and an example. Let me try those:

p@t:/opt/ros/kinetic/share/robot_localization$ roslaunch robot_localization ekf_template.launch
... logging to /home/p/.ros/log/5f5b9924-d910-11e7-9476-446d57e0983f/roslaunch-turing-20380.log
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.
error loading <rosparam> tag: 
    file does not exist [/opt/ros/kinetic/share/robot_localization/params/ekf_template.yaml]
XML is <rosparam command="load" file="$(find robot_localization)/params/ekf_template.yaml"/>
The traceback for the exception was written to the log file

and also:

p@t:/opt/ros/kinetic/share/robot_localization$ roslaunch robot_localization dual_ekf_navsat_example.launch
... logging to /home/p/.ros/log/5f5b9924-d910-11e7-9476-446d57e0983f/roslaunch-turing-20735.log
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

error loading <rosparam> tag: 
    file does not exist [/opt/ros/kinetic/share/robot_localization/params/dual_ekf_navsat_example.yaml]
XML is <rosparam command="load" file="$(find robot_localization)/params/dual_ekf_navsat_example.yaml"/>
The traceback for the exception was written to the log file

so I can't find how to launch the EKF node, and I also can't launch any example nodes, because i'm missing yaml?

I'm new at ROS, but I've done the tutorials. Please help me. What am I missing, besides a brain?