Customer Contract: How to create a contract with contract terms/primary contract document via REST?

Summary:

How do I create a customer contract, with attached contract terms (PDF file) as the primary contract document, using REST APIs?

Content (please ensure you mask any confidential information):

The Create contract documents REST API is only creating the document in the Contract Documents list. What's the API to use, to attach/upload the Contract Terms PDF file so that it appear as the Primary Contract Document?

Version (include the version you are using, if applicable):

24B

Code Snippet (add any code snippets that support your topic, if applicable):