Foundation for new deck

[Fialis]

Hello
We are planning our upcoming deck construction and have some questions regarding the foundation.
Since the distance between the patio door and the ground is not more than about 25 cm, we think it has to be a recessed joist that rests on ground slabs.

Do we need as many as in the sketch we have made?

Does anyone have any smart tips for leveling all the slabs?

/Fia

 

[Jonatan79]

Laying paving stones? Stylish, simple, and minimal maintenance. What type of house and plot do you have, are there any pictures?