What do Iranians usually do on the first day of the year?
During the twelve days that follow Nowruz, the idea is to visit family members and close friends. People often start with the closest elders (parents) on the first day and then other relatives, older relatives first, on the following days.
So what people do depends on their age and their place in the family. For example, my grandparents stayed at home on the first day because all their children (and grandchildren) visited.