How to start pumping?

Obie-One 💙💑👶

My baby will be 4w next Tuesday. I plan on getting a pump and starting to think about pumping to get some milk stored up. I will be a SAHM and will only need to get a backup supply for my SO to use if I am gone on errands. I currently have no need to try to up my supply. When would it be best to start pumping? How often should I pump? When is it best to pump?