Creating a 2D computational Domain in trixi

I want to create a 2D domain for simulation analysis in Trixi. The domain follows

a 2D domain of length 5400 mm and Height of 60 mm, which has 4 obstacles of length L= 12 mm and height H= 18 mm. These obstacles are placed on the lower sidewalls of the 2D domain. The distance from the left wall of the 2D domain to the obstacles are 250 mm, 550 mm, 850 mm, 1150 mm.

But I cant figure out how to write code for this. I want to use Treemesh for the mesh refinement. Please help, I am new to programming and julia.