The dune sounds like the coast.
You are allowed to bury something in the dune, right?
I have planned the double carport. But if you only have one car, at least a second parking space should be provided.
That now already looks a bit like a slope. Do you possibly have an elevation plan? You should have that for the planning.
The picket fence is the property boundary?
The neighbors have left about 3m free to the fence, is that also intended for you?