The MOVSM cannot be awarded for a single event. The award is written up on DA 638 and requires an O5 or above approval. The achievements must be of a sustained and direct nature (over a period of time) be to the civilian and military community, and not in conjunction with normal duties.
AR 600-8-22 para 2-23.
You will not receive a certificate as none exists. It is a service medal so the approved 638 is needed for you to add to your ERB but cannot be filed in your OMPF because it is not a downgraded award. I commend you on giving back to the community.