Re: Elevated gazebo
Build it the same way the deck was done. Set proper footings at the base of each post, then add 4' to the length of the posts to accommodate the elevation.
Pictures and plans are readily available across the internet for basic gazebo structures. If you've got reasonable building skills, then copying what you see won't be a problem. If you're not a competent builder, then leave the work for more experienced hands. Anytime safety is an issue, you don't want to mess around with things you're not comfortable or capable of.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!