An example of the id is a toddler that wanted a second helping of a dessert and whined until it was given to them.
An example of the ego is someone who works out and is very sweaty. They need to change their clothes and want to change in the car. They knew that anyone could see them changing their clothes, so they decided to find another place to do so.
An example of the superego is a cross country runner, during a race, who knew they could cut their time and come in first if they took a short cut. No one was watching but the runner would feel guilty, so they decided not to take the short cut.