The excerpt cited here is really intended as a way for the same individual to be working on the same files between multiple computers rather than multiple users between multiple computers. The problem being, like you described, version control and ending up with separate unique copies which would then need to be shared again. Being able to share the contents of a folder is a feature currently being developed. I know some people use Adobe Drive for this kind of workflow: http://www.adobe.com/products/adobedrive.html
This is the main reason I use Adobe. WHY IS THIS NOT EASY TO DO?!
Two people may not open a document at the same time
The Cloud is a web based version of a disk drive... Two people may not open a document at the same time
As far as I know, you may NOT open a document to edit it on the Cloud, you do the editing using a local file
You can use a combination of file syncing via the Creative Cloud desktop application and folder collaboration via the CC Assets site at https://assets.adobe.com to achieve collaboration on a single document.
The CC Assets site allows you to do Send Link for files and folders, which is a read-only public link. But you can also use Collaboration and give someone write access to the folder.
Now with that said you will need to use the Comments feature or some other method to not step on each other's changes. As one of you makes a change to a local file on your computer the change will sync up to the Creative Cloud and then sync back down to the other person's local file. You cannot lock a file.
From the file's 1-up page you can see the Version History and Restore to a previous version if needed.