Two girls! Girls, I want to wean my baby from breastfeeding, I have a …

Two girls! Girls, I want to wean my baby from breastfeeding, I have a question — how is it done? What is the whole process like? I’m a first-time mom and I don’t know how??? For example, say I wean her: do I need to pump afterwards? She only nurses on one breast; she hasn’t taken the other one since birth, and I’ve pretty much forgotten about that one for a year (((( By the way, does that one need pumping too??? Will there be any problems later?