I always just used very simple dxf's to import into DolphinCAD. You can use there own CAD programme to produce them but for me its very clucky so I produce them in one of the other CAD systems I have. What I do is save my dxf then open dolphinCAD then go to file menu then import then drawing then browse to where I saved the dxf. It should then open without too many issues, especially if its a very simple drawing which for Turn is all you need, an example of one is in the screenshot below. I have also attached a screenshot of what the part it (stainless end of these probe housings)
Hood