First lets get the buttons identified. Electronic 4 button watches are probably controlled by the same chip. Top left is the light button. Going clock wise S2 (Stop/Start), S1 (Reset), and S3 (Mode). Press S3 button (lower left) 3 times.- Tuesday flag and seconds should flash. Press S2 and Seconds will set to 00. Press S1 one time, Minutes flash and advance by pushing S2. Press S1 again and Hour digits Flash and S2 makes them advance. Continue through Date, Month, Day. When finished press S3