You might need to lay the bags on a cookie sheet at first to make sure they stay flat while freezing. Once frozen, the bags can either be stacked horizontally or stored standing up like books. Cover a pan of lasagna with plastic film first then put foil over it. Do the same for pies. It's a good idea to set your freezer temperature down low the day before you cook, but read your refrigerator manual for guidance.
Some models take cooling power away from the refrigerator part to cool the freezer.
Cool cooked food before putting it in the freezer. It should be no warmer than room temperature. To avoid overtaxing the refrigerator, you can cool it first by putting the pot of food in the sink with cold water. Transferring it out of the hot pot first works even better, but then there are more dishes to wash. Freeze in meal-sized portions.