To use the Governance Documents to link additional documents to an Action Item you can add the URL link from a Folder or an individual document link.
Folder (adding multiple documents)
Create a Folder in the Governance Documents
Add your documents to the folder
Copy the URL from the above bar
then Paste the URL into the Insert/Edit Link button to add to the Action
Documents -links to Individual documents
Click on the context menu at the end of the document and select Copy Link
As with the folder add the URL to the Action Item using the Insert/Edit Link button and Save