You will need to print out all the icons for the Holy Week services and laminate them. Using a board, divide it into three sections: on the left is the future, middle is the present and the right is the past. In the beginning of the week put all the icons on the left, as each day comes put the icon of the day in the middle with your child and read the scripture that goes with the Holy Week service.
Talk about the icon with your child, what do they see? What do they think the readings mean? Then the next day as you put a new icon in the middle simple move the old icon to the right on the past side.
Go to as many Holy Week services with your kids as possible for them to make the connection with the readings and the icons to the church. They will recognize the shift in the regular rhythm. Also, teach them the Behold the Bridegroom hymn or the Alleluia hymns that are sung in the church for the first 4 days.
Hope your Holy Week is gearing you up for Pascha!