Wherever your deck changes elevation you will need to pay special attention to how the respective levels are supported and attached to one another. It is usually best to frame one level at a time to provide a reference point to build from. Sometimes you may need to install blocking below the frame between posts of an upper deck to obtain a positive connection between decks and a smooth framing transition to a lower section. Any deck level not rigidly attached to a ledger on at least one side will require additional bracing between the posts and beams, or other methods of stabilization. Sometimes it is easier to build a platform on top of a deck to achieve a multilevel deck.