How can I get the id of the workflow run that triggered by API request?

I can use these codes to trigger a workflow, how can I get the run id?

curl \
  -X POST \
  -H "Accept: application/vnd.github.v3+json" \ \
  -d '{"ref":"ref"}'

This request will return, no id in the results.

Status: 204 No Content

And what dose the crated argument for /repos/{owner}/{repo}/actions/runs for? The doc has no detailed explaination about this created string query.