document the standalone executable

README.md

@@ -57,6 +57,20 @@ The remaining parameters are set to the their default values from the library. S
 
 See [tags_16h5_all.yaml](cfg/tags_16h5_all.yaml) for an example configuration that publishes all markers in the 16h5 family and [tags_16h5_filtered.yaml](cfg/tags_16h5_filtered.yaml) for filtering tags.
 
+## Nodes
+
+### Standalone Executable
+
+The `apriltag_node` executable can be launched with topic remappings and a configuration file:
+```sh
+ros2 run apriltag_ros apriltag_node --ros-args \
+    -r /apriltag/image_rect:=/camera/image \
+    -r /apriltag/camera_info:=/camera/camera_info \
+    --params-file `ros2 pkg prefix apriltag_ros`/share/apriltag_ros/cfg/tags_36h11_all.yaml
+```
+
+### Composable Node
+
 The composable node can be loaded into an already running component manager with a configuration file, by passing the configuration file path to `__params`:
 ```bash
 ros2 component load /ComponentManager apriltag_ros AprilTagNode \