A GPK is the GEOPAK equal to an ALG (InRoads)
The feature definition shown in the video was used to auto annotate and also auto store (or persist) the geometry to the native geometry (in this case a GPK)
You can use the example workspace provided with the software if you are not familiar with setting up a feature. Example geometry features are provided that will auto annotate and auto store geometry.
IMPORTANT: You do NOT need to auto annotate nor auto store geometry to set up stationing or station equation on an alignment.
To access the example workspace, set your Workspace to "Example" and set your Project to Bentley Civil Imperial or Metric.
you can also set the interface to Bentley civil.
HTH