SAM is the System for Atmospheric Modeling,download SAM in the http://rossby.msrc.sunysb.edu/~marat/SAM_Download but it need password and nameI am not sure what you mean about downloading SAM. If you mean CAM, the GitHub - ESCOMP/CAM: Community Atmosphere Model repo is not password protected.
Instructions for getting started with CAM can be found in the CAM6.3 User's Guide: CAM6.3 User’s Guide — camdoc documentation
OK,ThanksSAM is not a part of CESM nor CAM and we do not have any information on it. You will need to find your answer for this elsewhere.