Child Custody & Mental Harrassment

Hello Everyone, 1) I Got married in 2013. 2) Had a baby in 2016, but unfortunately the baby expired in 2017 due to epileptic reasons. 3) We adopted a girl child (we have a proper registered godnama from tehsil) 4) The child is now 2 years...happy and healthy....loved by everyone in family. 5) I and my husband had issues in our relationship since beginning, we don't share any physical and emotional bond since beginning but there was no big reason, hence never thought to get separated. Although in every fight, both said that we don't want to live with each other...but still we continued together for so long. 6) in Aug 2020, one incident happened and we had one physical fight, due to which I had many marks on my body, he hit me too much that day. And after much thoughts, I left home with the baby and stayed with parents for 8 months. 7) I still went back 2 months back, but the fights were continuous as now in-laws also have moved in permanently and my husband had ALWAYS prioritized in-laws before me and child. 8) There are a lot of financial issues, plus emotional and mental harassment to even leave my job and take care of child. Even though my child lives with her nani throughout the day during my office timings. Husband works from home as of now. 9) 5 days back, there was a big fight in which my husband and my FIL abused my father and me. I again left the house but in those arguments I was not able to take the child. My husband did not allowed me to take her while I left. Now, I want the child back and want to get separated legally. Please suggest what should be the FIRST STEP in doing so. Should I file a complaint in 1091 / or send notice / or directly file FIR. Thanks in Advance!