When to start building milk supply?

Da

My little man is just over two weeks old and is currently breastfed. (We do occasionally have to supplement formula but the last two-three days he has been nursed exclusively so we’re fairly confident he won’t need it much longer) I’ll be returning to work when he is 9 weeks old, so the middle of July. I’m not sure if my schedule when I return just yet but it’s a fairly safe bet he’ll need to be bottle fed at least 5 feedings a day. I’ve been told he’ll likely be drinking 4 ounces at that point so I’d need to have 20 ounces of milk pumped to send to the sitters with him. I would like to have 2-3 days ready before I go back to work, because even though I’ll be pumping at work I want to be prepared for a few days. When would my fellow working moms recommend I start focusing on building a supply rather than just feeding? What tips do you have to make sure I’m making enough to have a stash and my son is well fed without having to go back to formula supplementation? I’ve been drinking body armor since I’ve heard those help and i really enjoyed them during my pregnancy, but what other advice can I get from yall?