Pumping and freezing 101

I've been nursing my baby mostly on the breast, she occasionally takes a bottle from dad when I'm out but that rarely happens. She took formula when she was younger but now she's nearly three months and maybe has a bottle of pumped milk once a week if that.

I'm preparing to build a frozen supply for when I return to work. Any tips on how to begin? I don't know how much she usually takes as we don't use the bottle as much now, and I usually just pump 2oz to tide her over when I have an appointment/have to step away for more than two hours.

I have the kiinde system so I can pump directly to the bag and feed from it too - how much should I pump per bag?

By the time I return to work full time she will be 6.5 months so the milk will supplement the solids she's introduced to. How much should I expect to pump then? How often should I pump and at what times during my work day?