After creating or editing a workflow in the Rules Editor, your new version needs to be saved to make it accessible to other users of Modern Logic. And when you're ready, you can deploy your updated version to production, so that this updated logic will run when the API is called for this workflow.
On the workflow versions panel (accessible by clicking anywhere on the gray workflow graph), you will now see a new version at the top of the table. Click Save and give your new version a name, so that it will become visible to other users in the Rules Editor.
Once your version is saved, you can click Deploy at any time to promote your version to production.
Only one version can be in production at a time.