You will need to map the stocks to the presses you wish to print them on. Go into the stock mapping screen.

Add the stocks that you wish to map into the stock mapping section, tick on all stocks that you wish to map.

Choose what press you wish to map the stock to and click add. This is the same process if you want to remove stocks from the press just click 'Remove' instead of 'Add'.

You are able to see what stocks are mapped to each press at the bottom of the screen. Choose the press and it will load all the stocks that are mapped to that press.