The 'Printer Setup' window is where you choose which printer you wish to use, and how it should print.
Select the printer you wish to use from the drop down menu labeled 'Name' and the paper size from the drop down menu labeled 'Size'. If your printer supports multiple paper sources, you should select the paper source you wish to use from the 'Source' drop down menu.
Note: The 'Printer Setup' window may appear different and contain different elements depending on which Windows Operating System you are running. Even if your 'Printer Setup' window appears differently, it will have the same functionality as the one show above.