On the main Configuration Defaults pane you can edit the description of your template configuration set.
Expand the tree under Configuration Defaults to edit the template Configuration Parameters to be used as defaults for new models.
Expand the tree under Configuration Defaults to edit the template for default Configuration Parameters.
Edit Configuration Parameters that you want to apply to all new block diagrams.
Close the window to apply your changes.
Click Apply to apply your changes and keep the window open.
These values will be inherited by new block diagrams.