...
Now you have created a directory that both you and your collaborator can access. Because this is outside of the www folder you may will see in the Xythos interface it will not be publicly available. Only yourself, and people that you have granted access are able to access files in the folder. Once it is created, you can click on the folder, and use the Xythos toolbar to manage it (perhaps by adding more users,files, or delete deleting it).