Good links provided by qusys.
Think about what your internal processes are. You may have a marketing department that generates customer requirements. These have to flow down to product requirements. There may be some tracing between documents. Presumably you have reviews for the docs and a method to document and resolve issues. There's build and release processes. Maybe a separate group to do user documentation. Releases have to be coordinated with customers. And on and on...
Map out the flow and identify the stakeholders and where groups interact. Maybe that gets you going?