How to create a new card

One deck consists of one or more cards. Cards are used in WML to divide a deck's content up into small chunks. The card is a smallest unit of navigation. It is possible to navigate from one card to another within the same deck or to move to another deck.

In the element tree view window, select deck element (document) on the top of tree and press element button card to create new card.
In attributes window assign id attribute. You can use a key combination Ctrl + Arrow Up and Ctrl + Arrow Down to move card in elements tree. 

See also:

More about changing position of element in tree of wml elements.