Disciplining my toddler??

My son is 20 months old so he doesnt know right from wrong, my baby girl is 2 months old now and he is starting to hurt her, he screams in her face when shes crying jn her bouncy chair, earlier he threw a toy car at her head, and pushed her away when were laying in bed breastfeeding and also tries to kick, so I always gotta keep her close to me and I try my best to not get mad or overreact, I tell him that's not nice and that's booboo and make him sit on the couch when he gets mad, but he will get even more mad and slap me in the face or pull my hair.. idk what to do anymore.. I'm losing patience with him :(