Vensim's Subscript Control is used to manage which subscripts will be displayed for subscripted variables. If the model you are reading has no subscripts there will only be a -- tab. Otherwise there will be one tab for each subscript in the model.
Click on the subscripts you want to look at. You can get output for more than one subscript at a time, but the number of things to look at can quickly become large. For the simple version of this just click on a subscript element to toggle whether or not it will be shown.
If a subscript has a large number of elements the list of available elements will be shown on the left and the list o selected elements on the right. Click on an available element and click on the >> button to select it. Click on a selected element and click on the << button to unselect it.
