Hello everyone. Girls, please tell me, I want to express milk and free…

Hello everyone. Girls, please tell me, I want to express milk and freeze it so that when we go out, we can warm it up and give it to the child. I have an electric breast pump that is 100-125ml maximum from one breast at a time, this is even when the breast is full. How do I make sure there's a lot of milk, how many times should I express each day? And how long can I store the milk? And how should I store it properly? Do I need to express every day?