The version control repository functionality described on this page is only available in the full licensed edition of the Use Case Editor. The 'Lite' edition that is available for free download and use only allows you to save models to XML files and reload them from these files. Version control is not integrated in the 'Lite' edition.
Before models can be placed under version control, a model repository has to be created, then the first version of the model needs to be checked into the repository. Thereafter, models are checked out, edited, collisions are resolved, then the models are checked back in.
Open the Use Case Editor in the usual way, and make sure you have loaded your currently stand-alone model that you want to put under version control.
To create a new repository, from the main menu of the Use Case Editor, select File | Version control | Create version store ... . This will bring up an information dialog, warning you that once you have created a version store for a model, the name of that model can no longer be changed. You should make sure you are comfortable with the name of your requirements model before you create the version store.
Click OK in the dialog to go ahead and create the version store. You will have to select the folder location where you want the version store to be placed.
The version control store for your current model is created. Note that the structure of the version control store is that it creates a new child folder in the selected folder location, whose name is the same as the model you have open, but without the .xml extension. The model repository is then placed in that folder with the name versions.xz. For example, if your selected folder is C:\SomeDirectory and the standalone model file you have open is called MyModel.xml, regardless of the folder in which the standalone model came from, the version control store will be at C:\SomeDirectory\MyModel\versions.xz. Each actual stored version of the model goes into this same folder as numbered compressed model files, 1.xz, 2.xz, 3.xz etc.
Note that initially the model is not checked in, so the version store is completely empty.