Test Case vs Test Procedure. Are they seperate documents or treated as 1?

I had a look at the wikipedia article on the ISO IEEE software test documentation specification.

https://en.wikipedia.org/wiki/Software_test_documentation

Now it seems test case and procedure is treated sperately but then why are the procedures often part of the test case?

How I understand it is:

• I define my use cases without the steps and give those an ID.
• I create procedures. Each procedure also references a test case.

Would be great if you could explain this to me.