frozen milk

Trish
I exclusively pump and frozen my milk and my baby is 4 months old. I gave him fresh milk while storing extra in freezer bags. I tried to put lot of milk in one bag around 5-6oz while my baby drinks just 3-4oz in one feed. I dono how to use this milk as I want to use my stock now. Also I read I have to discard frozen milk in fridge within 24 hours wherein my milk is still hard ice in fridge if I leave for 24 hours( I live in New Jersey ) please help me and tell me how you use your frozen milk and how you feed your baby with frozen milk . What are dos and don't