Preterm labor?

Dolores • 25 👧 My family is my world ❤ 💙 R.I.P my little angels 5-29-13 👼 8-31-19 👼. Everything happens for a reason 💕 ❤💙
How do i know if im going through preterm labor? Im 30 weeks 2 days. im a first time mom so i dont know what to look for