For the paper, anything similar to the examples will be fine. You can use plain or patterned. Please try to make this type of cranes even if you know how to fold it another way. Practice with some scrap paper if this is your first time. It takes time to be able to get the folds to look good, so don't get frustrated if you see that your folds aren't matching up.
You may use 50 x 50mm (2x2 in) or 75 x 75 mm (3x3 in) paper. An occasional 118 x 118 mm (5x5 in) is okay, but not too many because we're going to send them 11,000 cranes, which will weigh a lot. You can choose to fold cranes for only one member or for all of them. You can also add short messages on them before you fold it, but don't forget to copy those messages onto another paper, or else they won't be placed in the book! And they must be in English, but you can translate them into another language if you'd like it to be written into the book as well.
When mailing the cranes, try to use a bubble mailer not too much bigger than the amount of cranes you'll put in so that it'll fit into the mailbox easily while still protecting your cranes. For even more safety, don't do the last step of pulling the wings out. Keep them flat so it won't get squished.
Make sure you include the messages you've written on another piece of paper. The book will also include a list of participants, so include your name (user/fake/real is your choice) and country as well. Write your email address too, so that when your package is received, you'll be informed and reassured that it all worked out.
Because not everyone signed up when we sent this email, here is some additional information we wrote to clear up any confusion about the cranes:
Mailing the Cranes: