Passing arbitrary strings to AppIntent

I'm using the TrailsSampleApp (in the AppIntentsSampleApp project which is provided by Apple. According to the code, if you use the "Get <trail> conditions with TrailsSampleApp" and provide a trail that is NOT in the suggested entities, it should pass control to the following TrailEntityQuery extension.

/// An EntityStringQuery extends the capability of an EntityQuery by allowing people to search for an entity with a string. extension TrailEntityQuery: EntityStringQuery {

/**
 To see this method, configure the Get Trail Info intent in the Shortcuts app. A list displays the suggested entities.
 If you search for an entity not in the suggested entities list, the system passes the search string to this method.
 
 - Tag: string_query
 */
func entities(matching string: String) async throws -> [TrailEntity] {
    Logger.entityQueryLogging.debug("[TrailEntityQuery] String query for term \(string)")
    
    return trailManager.trails { trail in
        trail.name.localizedCaseInsensitiveContains(string)
    }.map { TrailEntity(trail: $0) }
}

}

It says if you configure the Get Trail Info section in the Shortcuts App, control will be passed to this entities() function. However, it doesn't say how to configure it.

Any suggestions or help?