An example showing how to use the Lead Screw Joint is contained in the Simscape Multibody Parts Library, which is available on the MATLAB Central File Exchange. It provides parameterized parts for Simscape Multibody, gear assemblies, MATLAB code for extrusions. A screenshot of a model contained in the submission (>> sm_lead_screw_actuation_torque) is shown below.
The key step is making sure your CAD parts have frames in the correct location with the correct orientation. Compare them to this example and use Rigid Transform blocks to get them in the right spot.
--Steve
