As the person who wrote those directions here's the quick skinny:
1. Order the black sticker felt from the company link listed.
2. Cut the felt into circles of the appropriate size.
3. Peel up the existing pupils with your fingernail and rubbing alcohol.
4. Apply your newly made circles using a Gonzo photograph as a guide.
Presto! Easy peasy. Maybe it’s just my artistic perspective, but both sets of directions seem very straightforward to me. It basically is just applying your own stickers that look like the real thing.