Content can be added to a release from multiple places in the Contentful app: from search, from the entry sidebar, and from the new reference tree.
Content can be added in bulk by selecting the checkboxes next to entries in the Content tab during a search.
In the web app, click the Content tab in the top navigation.
Search for the entries that should be added.
Check the box next to each desired entry.
Click "Add to release". A dialog will appear, allowing you to select an existing release or to create a new release
Once a release is selected or created, the content will be added.
Content can be added to a release using the reference view for an entry. The reference view shows an overview of the content linked to from a particular entry, allowing for quick actions against the content.
To add content to a release via the reference tree:
Open an entry that contains nested references in the entry editor.
Click the References tab in the editor toolbar.
Select entries and assets from the list.
Click Add to a release in the sidebar.
Select or create a new release.
Finally, entries and assets can be added and removed from releases from the editor sidebar