If you are looking to physically (hand-made paper) rather than using a pattern:

Check your Etsy Purchases and Reviews page. Sellers often include specific IDs in the file names of their digital downloads.

You can recycle old paper or even paper bags by blending them into a pulp and pressing them onto the screens.

Sites like Patterns for Pirates or OKSew provide downloadable PDFs. If you bought it there, the ID might be part of your order confirmation email. How to Download and Use a ZIP Pattern File

Right-click the .zip file on your computer and select "Extract All" (Windows) or double-click it (Mac) to see the actual PDF files inside.