Hi! Thanks for checking out Link Viewer! Everything you need to know is in the "First Steps" Document that is displayed automatically when you launch Link Viewer for the first time. In case you want to see it outside Link Viewer, you can always find it here: Link Viewer First Steps PDF.
Note: The "First Steps" are displayed when no PDF was uploaded to Link Viewer. Delete all PDFs in Link Viewer to make it reappear.