The easiest way is to store your requirements project into a Project Folder shared on a network drive and use Exclusive Document Edit feature. This approach prevents multiple users from editing a document at the same time to prevent merge conflicts.
You can also store the project files (based on JSON format) in your preferred version control system (VCS). Reqview directly supports Subversion. You can also use other version control systems; just note that merging editing conflicts is error prone so we recommend using it together with the locking mechanism.
We are working on the next major update of ReqView (version 3), which will introduce ReqView Team Server, allowing seamless real-time team collaboration minimizing the resolution of editing conflicts. We also plan enable Git-like offline collaboration based on commits, branches and tags.