updated parameter management docs

docs/developer-guide/rosplane/parameter-management.md

@@ -28,8 +28,12 @@ To use the `param_manager` to define your own parameters, do the following:
 
 1. Declare an instance of `param_manager` in your class, or ensure that a parent class has a public or protected instance of `param_manager`.
 2. Initialize the `param_manager` object with a pointer to the ROS2 node object associated with the parameters.
-3. Use `param_manager::declare_param(std::string <PARAM_NAME>, <PARAM>)` to declare parameters of type double, bool, or string, where `<PARAM>` is the default value for the parameter.
+3. In the constructor, use `param_manager::declare_param(std::string <PARAM_NAME>, <PARAM>)` to declare parameters of type double, bool, or string, where `<PARAM>` is the default value for the parameter.
     - Use `param_manager::declare_int(std::string <PARAM_NAME>, <PARAM>)` to declare an integer parameter.
+4. In the constructor, use `param_manager::set_parameters()` to load any parameters that have changed on launch to the `param_manager` object.
+!!! note 
+    The `param_manager::set_parameters()` call is important when a node is loaded with parameters from a file on launch.
+    Not making this call will mean that the parameters stored in the `param_manager` object are out of sync with the ROS2 parameters.
 
 These steps will register your parameters with ROS2, allowing you to change them dynamically or load them from a launch file.
 
@@ -52,4 +56,14 @@ This file can be loaded at launch time so that all parameters are updated with t
 This means you don't have to change the default values in code (which would require a rebuild) to make sure a node gets launched with the correct values.
 
 To do this, add the `parameters=["/path/to/parameter/file"]` to a node's launch argument.
-See `rosplane.launch.py` for an example.
+See `rosplane.launch.py` for an example.
+
+## Updating Parameters
+Parameters can be updated from the command line using normal ROS2 commands.
+See the [ROS2 parameter CLI tools](https://docs.ros.org/en/humble/Tutorials/Beginner-CLI-Tools/Understanding-ROS2-Parameters/Understanding-ROS2-Parameters.html) documentation for more information on how to interface with these parameters from the command line.
+
+!!! note
+    Be sure to create a callback for your parameter changes, especially if you use a `param_manager` object.
+    ROS2 will send a list of changed parameters to this callback when the parameters are changed, allowing you to update the internally stored value in the `param_manager`.
+    Otherwise, your internally stored values will be out of sync with the ROS2 parameters, and it will likely not function correctly.
+    See the `controller_base` or `estimator_base` or `path_planner` code for an example of the callbacks.