Begin by writing down the alphabet in order on a piece of paper (or use the one below).
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Now pick a number between 1 and 25. Got it? I picked the number 3. Now, when you write down your coded message, instead of writing the realletter, you find that letter in the alphabet and count forward - as many letters as the number you picked.
So, if my message was "HI, HOW ARE YOU?" I would begin by finding the letter H, then counting foward three letters, to get the letter K. Then, since the next letter is I, find the I and count forward to get the letter L. Keep going through the whole message like that.
Uh oh...what about punctuation (like that question mark at the end of "Hi, HOW ARE YOU?"? Just leave that exactly the way it is.
Uh oh again! what happens when I get to the letter Y? I can't count forward 3 letters, because there aren't enough letters in the alphabet! That's okay...just start over at the beginning, after you count the Z. So Y becomes B!
Get the idea? Now you can try the Encoder at the top of the page. This encoder Shifts all the letters one, so an A becomes a B, a B becomes a C, and so on.