When you open your PDF in Adobe Reader (our PDFs cannot be opened in Corel Draw), go to View > Show/Hide > Navigation Panes > Layers to see the layers (sizes) available. The screenshots were done in the paid version, but the Layer option is in the same menu in the free version. You do NOT need to pay to get the layers functionality in Acrobat Reader. Just make sure you are using the desktop version. It will not work on mobile/tablet.
Click on the eyes to turn off the layers you do not need to have only your sizes visible. What you see on your screen is what will print.
Notice how the collage illustration also changes as you "turn off" layers. This allows you to see where your pattern pieces will be. If you are making a tiny size, you might be able to skip a few pages (the ones where you see no pattern piece) when printing, to save paper.