The Control Link window will appear or not appear depending on your computers screen size or resolution. You can easily access this however from any plugin window. In the upper right portion of the plugin window you will see a "Gear." Clicking that gear will reveal the Control Link windows. Also next to the gear will indicate what control surface device you are mapping (control linking) to. When this button is yellow that means you are in Focused Control Linked mode so you will map controls of Studio One when that particular plugin is open or in focus. When that button is not yellow, you are in Global Control Link mode. So anything you map will occur globally no matter what plugins you have open.