Coooparenting newborn

I decided to leave my relationship at 6 months pregnant, constant mental and verbal abuse. I can not take it anymore, I’m just curious how does co parenting a newborn look like? I plan to breastfeed till my child is about 8-9months. Can someone please help, I have no idea.. especially with a baby do young, I eventually want to do every other weekend but at what age does this start?