Uml diagrams question

Hey,
I’m new to uml diagrams. can any one help me?

A church market has different branches. Cashiers of each branch should be able to input all sales in their Point of Sales (POS) system. All transactions will be recorded in a local database. All transactions already recorded would be verified and validated first by staffs and then by the branch manager for each branch. After validation, information will be summarised before sent to the main office. The marketing manager may create planning and decision for the next month.
a. Draw an Activity Diagram of Transaction Reporting System.
b. Draw a Sequence diagram of all possible classes in the system.
c. Draw a possible State Diagram of a transaction.

Thanks
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