Access lists enable Users to be grouped together under one name, the name of the list, and then shared only with them.
The Family list, which you already have when you register, can contain from 3 Users maximum when you are not subscribed to as many Users as you want when you are.
Once you have subscribed, you can create as many lists as you like and put Users of your choice in them.
You can change these lists at any time, delete them and edit the content as you wish.