I have 2 documents. 1 is a draft, the other has already been published.
I want to create a release where the currently published document is archived and then the draft is published.
It looks like I can only schedule to publish in a release and the archive is "immediate" though
You can do both! To schedule the archiving of a document in a release, you only need to click on the unpublish option. It'll display a few options. Choose "Unpublish during a release", then add it to your existing release.
Fantastic. Thanks very much!