You can find basic apps for configuring routing policies at:
https://github.com/CiscoDevNet/ydk-py-samples/tree/master/samples/basic/ydk/models/policy
As usual, make sure you read the README file for basic apps. It explains how apps are named and how to run them.
https://github.com/CiscoDevNet/ydk-py-samples/tree/master/samples/basic
Check some of the policies against the examples in the guide to get started with OpenConfig:
https://github.com/CiscoDevNet/openconfig-getting-started/tree/master/models/policy
You'll get an idea of how the same policy can be configured with the XR native policy model or the OpenConfig routing policy model.
Enjoy!
