Ok, so you've got your piece of paper...
Fold in half hamburger style
Try to get it as neat as possible
Fold on side down to the end
Then do the same to the other side
Turn your paper so that the two open parts are facing away
Fold these two corners down like that, and do the same to the other side....
Now this part is a little confusing so look carefully
On that same side, on the top right corner, fold that remaining piece down
Then flip it over and do the same thing. But make sure it's the top right corner, and fold it TOWARDS you
Turn it upside down so it resembles a boat
Right in the middle, make a small tear, or cut (tearing is a lot more convenient)
Like this. Try to make it as straight as possible
Fold the sides down so you have two little flaps
AND, do the same to the other side
Finally, open the insides and fold the top and bottom together
And there's your beak!