@Stéphane ********
they want you to submit it as 1 PDF document.. it can have multiple pages and it can contain more than 1 thing you do. Go to your website where your photograps are and print it to PDF. You can print multiple pages if it looks ok, or one at a time and then combine the single pages you printed into 1 pdf document (there are free online pdf mergers). That's how I submitted mine. At first I just sent them links to my websites as a PDF document but that was rejected. Actual website content printed to pdf was accepted. I have included 2 completely different things I can do remotely, 1. was my 3d artist portfolio and 2. was my youtube channel video page.