I need help to design a sequence diagram for this scenerio:

Only the office Administrator is authorized to create a new transaction in the system. The admin credential must be verified against the system's database. Once verified the database will assign a login session for the user(Office Admin). Once verified, the office admin will be able to create a new transaction report with its own unique transaction id. Each transaction report with its ID will eventually be saved into the system's database. Once the user is done, he or she can then can close the form and sign off from the system.