alr2903:
Typically, a GE pushbutton range with Sensi-Temp will have the buttons for the Sensi-Temp burner marked Grill, 8", 6" and 4". There is also a Sensi-Temp dial marked with temperature and boil settings. In the large photo of Ben's Americana shown above, the Sensi-Temp dial is the bottom-most dial on the control panel at the right of the upper oven.
What you did was to press the correct button for what you wanted to use the burner for. Pressing Grill heated only the outermost coils of the burner, and on some models with a double-burner grill, it electrically interconnected the rear burner behind the Sensi-Temp unit with the Sensi-Temp unit, controlling both burners under the grill *. Pressing one of the numbered settings heated that surface area of the burner - 8 inches for the whole surface, 6 or 4 inches for smaller pots and pans. This feature would later be called Coil Select.
Once you pressed the button for what you wanted to do, you then used the dial to set the desired temperature.
There were also Sensi-Temp burners that could be varied only between an eight-inch and six-inch surface area; this depended on the model.
Hope this helps.
* On double-burner grill models, you did not turn the rear burner's controls on at all when using the grill; pressing Grill and using the Sensi-Temp dial controlled both front and rear. The Americanas shown are models that used a single-burner grill. Most double-burner grills were found on TOL 40-inch ranges.