Can anyone help me out for converting this file to cad file below is the link given.
https://grabcad.com/questions/can-anyone-help-me-out-for-converting-my-cad-surface-file-into-solid-file
I try fix your praoblem but All Surface in Your model are not connected correctly!!
you must fix the issues in your model, many surfaces ares proper connected, you have to seam all surfaces.