In the image sequence the Constraint Parameters are not shown.
When you create a ConstraintBlock on a BDD it will initially have an empty owned, applied, Constraint {} with no specification body, which can be edited inline on the symbol:
Make sure you have the Show Constraints symbol property enabled or you won't see it!
If you have more than one Constraint, one way of adding it is to use the specification dialog, where you can create a new owned Constraint and apply it.
Under the Common tab in the diagram sidebar there is a diagram menu item {} Constraint. If you click on that then on the ConstraintBlock it will create and apply a new Constraint but the Constraint will not by default be owned y the ConstraintBlock it was applied to!.