Azure devOps on premise, how to generate subscription ID to create resource pool

Question

Hi,

I'm currently exploring Azure DevOps (in an on-premise environment), I'm trying to build a pipeline, but it failed due to this error:

There was a resource authorization issue: The pipeline is not valid. Could not find a pool with name Azure Pipelines. The pool does not exist or has not been authorized for use. For authorization details, refer to https://aka.ms/yamlauthz

I tried to click the "Authorize resources" button, but it was still failing, and It seems because I really do not have any resource pool, that's why it's not able to get authorized. Tried to create a resource pool, but it's asking me for the Subscription ID. As this is an on-premise exploratory environment, I couldn't get/used any Subscription ID from azure portal (portal.azure.com).

Any advice on how to solve this problem is appreciated. Thank you.