Is it a single or multi-level deck? Explain what you can about what you're interested in doing, and why.

A deck is not an inexpensive item to add to a backyard. I'd really recommend finding a local professional here on Houzz and have them draw up a plan for you. If it doesn't have good circulation and functionality you will be wasting your money. They will ask you more questions about how you will use the space, what is your budget, and preference for materials.

Good luck!

James

Even if you're not designing the deck yourself, but trying to work out the concept, eventually, you'll need to prepare a "to scale" base plan, which mainly shows house footprint, walks, drive, major trees, fences etc. ... anything nearby that will affect or be affected by the project. The base PLAN is how you (or anyone) can understand the 2-D space of the yard.

Why a gazebo? What do you expect to gain by incorporating it into the deck. Is this a DIY project or you'll hire it out?

In addition to a base plan, in order to get help here, you'll need to provide photos. One scene should be taken with your back to the house, showing the outward bound view, from side to side across the entire yard. The other scene that needs to be seen is the view from the middle of the back yard looking back toward the house, showing it from end to end with some extra space at each end. It will require seeing all these things in order to help you with the concept.

(To show a "scene" have the camera remain in ONE spot while you pan from left to right taking slightly overlapping photos.)