To set the properties of a model, first view the models in the continuum using the object tree, then right-click on the selected model. This will cause the Properties and Expert properties to become available for inspection and editing.
As a general rule, unless you are thoroughly familiar with the theoretical aspects of the model and the discretization techniques used in STAR-CCM+, we recommend that you not make any changes within the Expert category. The values in that category reflect both the model's design and discretization approaches that have been optimized for accuracy and performance. Tampering with them may diminish the effectiveness of the model.