That is the complete keyboard. The method for using it is this:
The message is written out in plain text; for example:
DESTROY BRIDGE AT ONCE
(Only capital letters are commonly used in cipher work.) This message is now divided into groups of two letters, in the same order, so that it reads:
DE ST RO YB RI DG EA TO NC EX
(The X is added to complete the group and is called a null.) These groups of twos are now ciphered from the keyboard into other groups of twos, by the following method:
Where two joined letters of the original message appear in the same horizontal row on the keyboard, the next letter to the right is substituted for each. Thus, the first two letters of our message are DE. They occur in the same horizontal row on our keyboard. Consequently, for D we write E, and for E we go “on around the world” to the right, or back to the other end of the row, and write G for E. This gives us DE enciphered as EG.
Where two joined letters of the original message appear in the same vertical row on the keyboard, the next letter below is substituted for each.
Where two joined letters of the original message appear neither in the same horizontal nor the same vertical row on the keyboard, we imagine a rectangle with the two letters at the opposite corners, and in each case substitute the letter found on the keyboard at the other corner of the same horizontal row. This looks complicated, but in reality is very simple. For example, take the third two-letter group of our message—RO. The rectangle in this case is