How did you model these surfaces ?

I'd start with some control sketches and planes to establish the footprint, the tabletop and the (triangular?) cross sections at the bends.

Next, either 3d sketches (which attach to the control sketches, because by themselves, 3d sketches are a major headache) to finish out the wireframe and lofted planar surface features of each facet, to be knitted and solidified at the end,
or,
2d sketches and lofts which reference the control sketches.

I think I'd be faster doing it the first way but the second way would have a prettier feature tree.

I would NOT make it in an assembly. Assembly context references are even worse behaved than free range 3d sketches!

Robert's plan sounds good.
It is not exactly the same, but you could see how these letters are made: Prismatic Font Sample

They have a prismatic type of shape to them, and are similar to the table in construction.

Pobably that this form this can be done in sheet metal