I m also having the same prob as you. I dont know how to start to pump and store. I exclusively pump for my first son so is quite straight forward. now i m latching my daughter and i kept on procrastinating on pumping. Actually, if you pump after every feeding, you will have more supply over time. so should be fine. I am actually waiting for my daughter to go 4 hours without feeding then i pump in between. at least the refilling is more. but then looks like i have to start pumping soon else she's going to refuse the bottle.
My mother in law also the caregiver. she is bugging me to start pumping soon as she's worried that baby will refuse to let them feed later. so ,i think is a very valid concern. my mother in law is also taking care of my elder son(i suppose your mother in law also taking care of elder child?) if that is the case, mayb a good idea to spare a thought for her. mayb on sundays, one feed let your hubby feed? also bonding for him and baby.