Update your contact information now and whenever you have a change. You may update your account anytime - under Association menu - select Edit My Account.
It is combined and shown as a Family Account. There are 2 guardian/parents that may be associated with each of your players. Open each name and modify their individual contact information. If only one guardian/parent, you may add another.
Questions about the website - look under the menu heading Association then Using This Site. It also explains why duplicate notifications for you and your player if you are a volunteer.