Child support

Hey ladies. I just want some input on child support. My daughter is 3 now that she is I preschool things got expensive. I'm working a full time & a part time job. Her dad is in her life but financially has not helped out at all even when we were together his mom would buy me anything I needed so he never bought our daughter anything she needed. We are sort of in good terms but he acts like just because she lives with me that he doesn't have to provide for her at all... How does it work?