When I open the STEP file it comes in as a surface. This will need thickness to covert to sheet metal. All edges will need to be perpendicular to the adjacent main surface and if you just thicken the surface those edge (material thickness) might not automatically be perpendicular. You will need to make cuts in the corners for bend relief. You also might need to add radii on all bend corners and the inside radius must be equal to the outside radius minus the part thickness.
