Hi Op - it sounds like you might find a primer on pumping helpful, susan of Arlington lactation offers a great pumping class, there is one coming up this Saturday at 10am:
https://www.arlingtonlactation.com/copy-of-class-offerings
Unless your baby goes straight to the NICU you do not need to start pumping right away, at all. Hand expression during the first few days after birth has been shown to be helpful but otherwise absolutely you do not need to be using a pump! And like others hve said it can be harmful as you could create oversupply (this may sound good but let me tell you from experience, it’s not!) Only other reasons you might pump are if you ar having a lot of pain and needs to give your nipples a brief rest for a few sessions while they heal and you see an LC and get figured out what is causing the pain. Or if your baby is have serious trouble latching. Again in those instances you should see an LC immediately to have them give you a plan for when to pump. Barring all these things, which likely won’t happen, focus on building your relationship with baby at the breast. Work on latching at the breast and getting your both comfortable there. If after a few weeks and you are returning to work quickly you can think about pumping some, maybe one morning session but it really isn’t necessary. When you return to work you only need one day of supply and then you will be creating that supply when you pump each day, so don’t let anyone get you super worried about building up a stash.
And in addition to the pumping class above I would take a breastfeeding basics class to help you get some of your questions answered. I didn’t see Susan having one coming up but you could email her and she might send the recording of her last one. Or the Washington DC breastfeeding center has good ones