Move fields to content edit form sidebar with Field Group module

Content entity forms get a Vertical Tabs element which is often displayed as the sidebar in content edit forms.

The Field Group module can add items to the vertical tabs.

1. Create a field group in your content type's manage form config.
2. Configure the field group type as Details Sidebar.
3. Place fields in the group.

The Vertical Tabs submodule will create an extra vertical tabs display, so don't use that unless you mean to.