This is an URL-changing riddle, meaning that at most levels (if it's different you will notice) you will have to change the URL in the address bar of your browser to proceed to the next level.
To prevent the possibility of jumping ahead by accident (you wouldn't want to miss any level, would you?) you have to enter the current level number after your answer (and before the .php).
So if you are on level 9 and the answer you found is doodlebug (answers will never contain capital letters or spaces) you would change the address to:
If your answer is correct you should end up on level 10 that way.
Google and Wikipedia will be very helpful to gather information you don't already know yourself. If you still end up stuck on any of the levels, you can find some helpful souls on the Nordinho Forums. But please don't spoil this riddle for the others by posting full solutions or answers.
Origami Riddle World