How do you begin pumping to return to work/school?

Chantel
Hi, I'm a FTM and I will be beginning a class soon. It's once a week for 8 hours. My LO will be 4 weeks on Friday. Should I start pumping (giving a bottle) this week? How often? The class starts 2/13. She'll be 6weeks & 1 day. Help!! I don't want my LO starving or my supply dropping.