The Optimization page is opened when you select "Optimization" in the side bar menu of the Circuit Settings dialog box which allows you set up the frequency sweeps for your simulation. There are two tabs on the Optimization page: Goals and Results. The Goals tab allows you to define the analysis frequencies and goals for your optimization and the Results tab allows you to use the results of your optimization. For more details, click on the tab name below.
For more information on how Sonnet performs an optimization, see in the Optimization in the Parameterizing your Project chapter in the Sonnet User's Guide.