The Center checkboxes that read L-R and T-B just stand for Left-Right and Top-Bottom; checking those will center the printed image on the page, both horizontally and vertically.
You can select your Paper options by size—a number of preset sizes, from letter to legal to any number of commonly used formats—and by Source, which will define which paper tray on your printer that the paper feeds from. You can just leave it on Automatically Select unless you’re using a printer that has more than one paper tray with different size pages in each tray.
Orientation defines if the image prints in Portrait style (with the paper turned upright) or Landscape style (with the paper turned sideways). For images that are greater in width than height, Landscape is usually best.
Layout lets you choose to print only the first frame, or all frames—and also the scale, as you can leave it at actual size or scale it down or up to fit on the page. The Layout option is the most fun; if you leave it Actual Size, you’ll just get one frame per page. But you can set it to automatically scale—and also set it to StoryBoard, which has three different layouts that let you put the frames in a storyboard grid across the page.
