Please submit a ticket here to request Sandbox access. Select "API request" as a type. Please make sure to include the email you want to be associated with the Sandbox account.
Once access is granted, you can start building the integration.
What is the sandbox environment?
The Sandbox environment mirrors the Orkestro production environment. This is where you can test your integration without fear of sending wrong information, geocoding issues etc. Sending jobs into this environment will mean couriers are not booked and you can deploy and test changes to see if they will work.