Dilated 1cm

I had a long morning. I woke up at 5 am with strong pain in my upper abdomen, went to the hospital around 6-7am, and found out i was dilated a little over 1 cm and had two contractions during the time i was there (i didnt feel any of the contractions), they made me wait maybe about an hour to see if i was going to go into labor (thankfully i didnt) and got sent home. This is my first pregnancy(36 weeks along) and I am 18 years old. I just wanted to know for the mothers who've already had their beautiful babies, how do you know if you're having contractions and how do you know if your water breaks? Is there a type of smell and color?