Boyfriend's Baby Is Here

Okay so there's kinda a lot to unfold here. So my boyfriend has a one week old daughter. He had a one night stand with a women a month before we got together. After she had found him and told her she was pregnant, my boyfriend said I didn't have to stay if I didnt want to. I really liked him. I wasn't so sure about the whole stepmother thing, but I cared about him so I thought I could do this. About 6 months into our relationship, I ended up having a fight with my parents and got kicked out. He let me move in with him. He hadn't really talked to the mom much. She didn't want him at the appointments. Turns out the reason was because she wasn't even going to appointments regularly. She was doing drugs. The day the baby was born, it was a girl, but CPS was called because they found drugs in the babies system. My boyfriend wanted a DNA test from the very beginning, so they had to arrange for that. Baby is his. I guess his baby mama said since she's breastfeeding they can't take the baby away. Though I doubt Cocaine breast milk is good for a baby. Fast forward a few days, he's got full custody. He hasn't asked me to do anything. He's got a month paternity leave and then he's gonna try to find a daycare. As his gf and I'm living with him and love him so much I feel I should be helping. I just don't know how. I've bought some books on parenting and some on step parenting. I want to have him and this little girls back, but I've never been a parent before. Plus I had shitty parents so no good examples, like where do I go from here? How does this parenting thing work?