Just below the larger button on the side is a small recessed button. Use a pin to push it in to set the time and date. Pushing it twice will bring you to the month setting-use the large button to set to the correct month. Push the smaller button again for the day, hour and minutes using the larger button each time to set the correct number.

PJ Masks Kid's Light Up Spinner Red Digital Watch with Pop Up Feature,Accutime,4331780867