How to express/pump AND still breastfeed?

I’ve just started expressing breast milk as it’s becoming unrealistic for me to always be with bub to breastfeed.

However, I still wish to breastfeed most of the time when can be with bub. I’d like to express enough to collect about 2-3 feeds per day + 1-2 feeds to freeze.

But it’s so very confusing! When is the best times to pump to achieve this? Mummas who pump and breastfeed, what is your schedule?

PS. my baby is 3 weeks old and taking about 70mL currently and feeds around 8-10 times per day. If I have a full boob in the early morning, I can express close to 150mL from the single boob.