Create a new issue using app link between JSM and Jira OnPrem 8.13.5

Please help me see what I am missing.

I have successfully created an app link between our JSM cloud env. and our On Prem Jira v 8.13.5. I can link and un-link issues between the sites. But, how do I create a new issue on the on prem installation from an existing issue in JSM?

It seem there should be a way to do it the other way but we want to do it from the cloud to the on prem (nor do I actually have that option in the on prem version, but that is anyway not what we want so that is ok).

Do we need to use webhooks or should this be as easy as linking the issues?