After opening the project file, navigate to the View pane and click the catalog button.

Then, navigate to the RouteAPI Python Toolbox to access the Closest Facilities Toolbox script.

API Documentation: Closest facility routing API

The script requires five parameters, with the first and third being the most crucial for achieving the desired output and accuracy.

Refers to the starting points on the map when looking for closest facilities to route to.

While filter is depending on incidents, it can query those incidents based on the attributes of the data.

Refers to the list of destinations that the route will consider as a potential 'closest' facility from the given incidents.

Both of the above parameters are in the forms of feature layers. What are feature layers? A feature layer is a layer containing a grouping of similar features and their associated properties. Feature layers are how ArcGIS Pro represents feature classes. They are the most commonly used layer type. Feature layers can use data from any source that provides point, polyline, polygon, multipoint, or multipatch vector feature data. Often these are feature classes contained in a geodatabase, but many others exist, including shapefiles and online feature services (the data source for web feature layer).

The map that the script will use and refer to throughout the duration of the script run. Usually this will just be the current map.

The name of the layer that the result from the toolbox run will be written to.

When the tool is running, click on View Details to view the tool's progress and use this to debug if needed.

To get the result on the map, after running the toolbox, check the new layer that we just created, in this case, check "demo".