Help me with a Project with 7 segment display (multiplexed) with push bu

Arduino mega 2560 When the circuit is energized, the 7-segment display must show a zero number until a button is pressed

if you press the first button you must start the ascending count

if you press the second button you must start the descending count

if the third button is pressed, the account must be paused If the first and second pushbuttons are pressed at the same time, the account must start at zero

What help do you need?

Is this a college assignment?

Show is the circuit diagram.

Show us your code.