Question for breastfeeding and pumping mommies! Okay I go back to work in a month and I'm trying to…

Question for breastfeeding and pumping mommies! Okay I go back to work in a month and I'm trying to get a stock pile of milk for my mom while she's watching her since I work 8 hour days. How often should I pump a day? I've only been pumping once a day cause I'm scared in not gonna have enough for my daughter for the rest of the day if I do it more than that 😕 FTM and no one in my family has ever breastfed so I have no one to ask