One thing that might be understandably throwing you off is that screens aren't made up of cells (technically), they are made up of references to cells. So if you have a cell that displays the clock, and you use it on screen 1 and screen 2, there is really only a single cell "clock", and both screens reference it. If you make changes to the clock cell, those changes will be reflected on both screens. If you want to have the clock cell on screen 1 be different from the clock cell on screen 2, you'll need to make a copy of the clock cell and use one of them on screen 1 and the other on screen 2.