When should I pump?

My baby is mostly bf but she gets at least one bottle a day so she can bond with her dad, but I'll be going back to work pretty soon and I'm trying to build up a supply but I don't know how? I don't know when or how often I should be pumping to build it. Currently I usually go between two and three feedings in my fridge at a time. I think I only manage that much because I have these little shells I wear that catches leakage during the day, and I save it. This is my first baby so I dont know what to do at all.

And do you all have any suggestions for hydration? I drink almostly solely water and have started drinking body armor drinks to help but I still feel like I'm not hydrated?