Hello Milo!
In your lab (when it is finished setting up) you will be able to access RPC on the server 10.10.20.100 - credentials are found in the lab. You can open the application "PhoneView" that has an icon on the desktop. For any questions related to your IVT and using its tools, please refer to the lab guide found here:
https://devnetsandbox.cisco.com/Docs/EP/DevNet%20Sandbox%20IVT%20Lab%20Guide-EP-2.pdf
Please let me know if you have any additional questions! When your lab is setup, I can coach you through using PhoneView via WebEx.
Thanks!
Jacob